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CXX

 *Conan The Librarian

    The CXX command invokes the C++ compiler to compile C++ source
    programs. The syntax is as follows:

         CXX file-spec,...  +library-file-spec/LIBRARY...

    Qualifiers indicate special actions to be performed by the
    compiler or special input file properties. Compiler qualifiers
    can apply to either the CXX command or to the specification
    of the file being compiled. When a qualifier follows the CXX
    command, it applies to all the files listed. When a qualifier
    follows the file specification, it applies only to the file
    immediately preceding it.

    For help on the C++ Class Library, type

       $ HELP CXXL

    For help on the Standard Library, type

       $ HELP CXXLSTD

    An HTML version of this online help is accessible from:

       file:/sys$common/syshlp/cxx$help/cphelp.htm

  1 - Command Parameters

 file-spec,...

    One or more C++ source files separated by plus signs or commas.
    If plus signs are used, the input files are concatenated into
    a single object file. If commas are used, each file is compiled
    separately to create separate object files. If no input file type
    is specified, C++ assumes the .CXX default file type.

 library-file-spec

    A text library containing #include modules referenced in one
    or more of the source files. A library file specification must
    be concatenated with a file specification with a plus sign and
    qualified using the /LIBRARY qualifier. If the input file type is
    not specified, C++ assumes the .TLB default file type.

    Format

      CXX

  2 - Qualifiers

 2.1 - /ALTERNATIVE_TOKENS

       /ALTERNATIVE_TOKENS
       /NOALTERNATIVE_TOKENS

    Enables use of the following operator keywords and digraphs to
    generate tokens:

    Operator
    Keyword         Token

    and             &&
    and_eq          &=
    bitand          &
    bitor           |
    compl           ~
    not             !
    not_eq          !=
    or              ||
    or_eq           |=
    xor             ^
    xor_eq          ^=

    Digraph Token

    :>      ]
    %:      #
    %>      }
    <%      {
    <:      [

    The default is /NOALTERNATIVE_TOKENS when compiling with the
    /STANDARD=ARM, /STANDARD=MS, or /STANDARD=RELAXED option.
    The default is /ALTERNATIVE_TOKENS when compiling with the
    /STANDARD=STRICT_ANSI or /STANDARD=GNU option. Specifying
    /ALTERNATIVE_TOKENS also defines the __ALTERNATIVE_TOKENS macro.

 2.2 - /ANSI_ALIAS

       /ANSI_ALIAS
       /ANSI_ALIAS (D)
       /NOANSI_ALIAS

    Directs the compiler to assume the ANSI/ISO C aliasing rules,
    which gives it the freedom to generate better optimized code.

    /NOANSI_ALIAS specifies that any pointer can point to any object,
    regardless of type. /ANSI_ALIAS specifies that pointers to a type
    T can point to objects of the same type, ignoring type qualifiers
    such as const, unaligned, or volatile, or whether the object
    is signed or unsigned. Pointers to a type T can also point to
    structures, unions, or array members whose type follows the rules
    above.

    The aliasing rules are further explained in Section 3.3,
    paragraphs 20 and 25, of the ANSI C89 Standard (Section 6.3 of
    the ISO version, same paragraphs).

 2.3 - /ARCHITECTURE

       /ARCHITECTURE=option
       /ARCHITECTURE=GENERIC (D)

    Determines the Alpha or Intel processor instruction set to be
    used by the compiler. The /ARCHITECTURE qualifier uses the same
    keyword options (keywords) as the /OPTIMIZE=TUNE qualifier.

    Where the /OPTIMIZE=TUNE qualifier is primarily used by
    certain higher-level optimizations for instruction scheduling
    purposes, the /ARCHITECTURE qualifier determines the type of code
    instructions generated for the program unit being compiled.

    OpenVMS Version 7.1 and subsequent releases provide an operating
    system kernel that includes an instruction emulator. This
    emulator allows new instructions, not implemented on the
    host processor chip, to execute and produce correct results.
    Applications using emulated instructions will run correctly, but
    may incur significant software emulation overhead at runtime.

    All Alpha processors implement a core set of instructions.
    Certain Alpha processor versions include additional instruction
    extensions.

    Select one of the /ARCHITECTURE qualifier options shown in the
    following table.

    Option                Usage

    GENERIC               Generates code that is appropriate for all
                          processor generations. This is the default.
    HOST                  Generates code for the processor generation
                          in use on the system being used for
                          compilation.

                          Running programs compiled with this option
                          on other implementations of the Alpha
                          architecture may encounter instruction-
                          emulation overhead.
    ITANIUM2 (I64 only)   Generates code for the Intel Itanium 2
                          processor family. For use on I64 systems
                          only.
    EV4 (Alpha only)      Generates code for the 21064, 21064A,
                          21066, and 21068 implementations of the
                          Alpha architecture.

                          Programs compiled with the EV4 option run
                          without instruction-emulation overhead on
                          all Alpha processors.
    EV5 (Alpha only)      Generates code for some 21164 chip
                          implementations of the Alpha architecture
                          that use only the base set of Alpha
                          instructions (no extensions).

                          Programs compiled with the EV5 option will
                          without instruction-emulation overhead on
                          all Alpha processors.
    EV56 (Alpha only)     Generates code for some 21164 chip
                          implementations that use the byte and word-
                          manipulation instruction extensions of the
                          Alpha architecture.

                          Running programs compiled with the EV56
                          option might incur emulation overhead on
                          EV4 and EV5 processors, but will still
                          run correctly on OpenVMS Version 7.1 (or
                          higher) systems.
    PCA56 (Alpha only)    Generates code for the 21164PC chip
                          implementation that uses the byte- and
                          word-manipulation instruction extensions
                          and multimedia instruction extensions of
                          the Alpha architecture.

                          Programs compiled with the PCA56 option
                          might incur emulation overhead on EV4,
                          EV5, and EV56 processors, but still run
                          correctly on OpenVMS Version 7.1 (or
                          higher) systems.
    EV6 (Alpha only)      Generates code for the 21264 implementation
                          of the Alpha architecture.
    EV68 (Alpha only)     Generates code for the 21264/EV68
                          implementation of the Alpha architecture.
    EV7 (Alpha only)      Generates code for the EV7 implementation
                          of the Alpha architecture.

    See also /OPTIMIZE=TUNE, which is a more typical option.
    Note that if /ARCHITECTURE is explicitly specified and
    /OPTIMIZE=TUNE is not, the tuning processor defaults to the
    architecture processor; for example, /ARCHITECTURE=EV6 implies
    /OPTIMIZE=TUNE=EV6.

 2.4 - /ASSUME

       /ASSUME
       /ASSUME=(option[,...])

    Controls compiler assumptions. You may select the following
    options:

    Option                 Usage

    [NO]WRITABLE_STRING_   Stores string constants in a writable
    LITERALS               psect. Otherwise, such constants are
                           placed in a nonwriteable psect. The
                           default is NOWRITABLE_STRING_LITERALS.
    [NO]ACCURACY_          Specifies whether certain code
    SENSITIVE              transformations that affect floating-point
                           operations are allowed. These changes
                           may or may not affect the accuracy of the
                           program's results.

                           If you specify NOACCURACY_SENSITIVE, the
                           compiler is free to reorder floating-
                           point operations based on algebraic
                           identities (inverses, associativity, and
                           distribution). This allows the compiler to
                           move divide operations outside of loops,
                           which improves performance.

                           The default, ACCURACY_SENSITIVE, directs
                           the compiler to use only certain scalar
                           rules for calculations. This setting can
                           prevent some optimization.
    [NO]ALIGNED_OBJECTS    Controls an optimization for dereferencing
                           pointers.

                           Dereferencing a pointer to a longword- or
                           quadword-aligned object is more efficient
                           than dereferencing a pointer to a byte-
                           or word-aligned object. Therefore, the
                           compiler can generate more optimized code
                           if it makes the assumption that a pointer
                           object of an aligned pointer type does
                           point to an aligned object.

                           Because the compiler determines the
                           alignment of the dereferenced object
                           from the type of the pointer, and the
                           program is allowed to compute a pointer
                           that references an unaligned object (even
                           though the pointer type indicates that
                           it references an aligned object), the
                           compiler must assume that the dereferenced
                           object's alignment matches or exceeds the
                           alignment indicated by the pointer type.

                           The default, /ASSUME=ALIGNED_OBJECTS,
                           allows the compiler to make such an
                           assumption. With this assumption made,
                           the compiler can generate more efficient
                           code for pointer dereferences of aligned
                           pointer types.

                           To prevent the compiler from assuming
                           the pointer type's alignment for
                           objects to which it points, use the
                           /ASSUME=NOALIGNED_OBJECTS qualifier.
                           This option causes the compiler to
                           generate longer code sequences to perform
                           indirect load and store operations to
                           avoid hardware alignment faults for
                           arbitrarily aligned addresses. Although
                           /ASSUME=NOALIGNED_OBJECTS might generate
                           less efficient code than the default
                           /ASSUME=ALIGNED_OBJECTS option, by
                           avoiding hardware alignment faults, it
                           speeds the execution of programs that
                           reference unaligned data.
    [NO]GLOBAL_ARRAY_NEW   Controls whether calls to global array new
                           and delete are generated as specified by
                           ANSI. Pre-ANSI global array new generated
                           calls to operator new(). According to
                           ANSI, use of global array new generates
                           calls to operator new()[]. The GLOBAL_
                           ARRAY_NEW option also defines the macro
                           __GLOBAL_ARRAY_NEW.

                           GLOBAL_ARRAY_NEW generates calls to
                           operator new()[] for global array
                           new expressions such as new int[4];
                           this is the default when compiling
                           /STANDARD=RELAXED, /STANDARD=STRICT_ANSI,
                           /STANDARD=GNU, and /STANDARD=MS.

                           NOGLOBAL_ARRAY_NEW generates calls to
                           operator new() for global array new
                           expressions such as new int[4]; and
                           preserves compatibility with Version
                           5.n; this is the default when compiling
                           /STANDARD=ARM.
    [NO]HEADER_TYPE_       Controls whether the compiler appends a
    DEFAULT                file extension to a file name. The default
                           is /ASSUME=NOHEADER_TYPE_DEFAULT. To
                           prevent the compiler from appending a file
                           extension to files (such as STL header
                           files that must not have file extensions)
                           use the /ASSUME=NOHEADER_TYPE_DEFAULT
                           qualifier.
    [NO]MATH_ERRNO         Controls whether intrinsic code is
                           generated for math functions that set
                           the errno variable. The default is
                           /ASSUME=MATH_ERRNO, which does not allow
                           intrinsic code for such math functions to
                           be generated, even if /OPTIMIZE=INTRINSICS
                           is in effect. Their prototypes and call
                           formats, however, are still checked.
    [NO]POINTERS_TO_       Controls whether the compiler can safely
    GLOBALS                assume that global variables have not had
                           their addresses taken in code that is not
                           visible to the current compilation.

                           The default is /ASSUME=POINTERS_TO_
                           GLOBALS, which directs the compiler to
                           assume that global variables have had
                           their addresses taken in separately
                           compiled modules and that, in general,
                           any pointer dereference could be accessing
                           the same memory as any global variable.
                           This is often a significant barrier to
                           optimization.

                           While the /ANSI_ALIAS option allows
                           some resolution based on data type,
                           /ASSUME=POINTERS_TO_GLOBALS provides
                           significant additional resolution and
                           improved optimization in many cases.

                           The /ASSUME=NOPOINTERS_TO_GLOBALS option
                           tells the compiler that any global
                           variable accessed through a pointer
                           in the compilation must have had its
                           address taken within that compilation.
                           The compiler can see any code that takes
                           the address of an extern variable. If it
                           does not see the address of the variable
                           being taken, the compiler can assume that
                           no pointer points to the variable.

                           Note that /ASSUME=NOPOINTERS_TO_GLOBALS
                           does not tell the compiler that the
                           compilation never uses pointers to access
                           global variables.

                           Also note that on I64 systems, the
                           NOPOINTERS_TO_GLOBALS option is ignored
                           and should not cause any behavior changes.
    [NO]STDNEW             Controls whether calls are generated to
                           the ANSI or pre-ANSI implementation of
                           the operator new(). On memory allocation
                           failure, the ANSI implementation throws
                           std::bad_alloc, while the pre-ANSI
                           implementation returns 0.

                           /ASSUME=STDNEW generates calls to the ANSI
                           new() implementation; this is the default
                           when compiling with /STANDARD=RELAXED,
                           /STANDARD= STRICT_ANSI, and /STANDARD=GNU.

                           /ASSUME=NOSTDNEW generates calls to the
                           pre-ANSI new() implementation; this is the
                           default when compiling with /STANDARD=ARM
                           and /STANDARD=MS.
    [NO]TRUSTED_SHORT_     Allows the compiler additional assumptions
    ALIGNMENT              about the alignment of short types that,
                           although thought to be naturally aligned,
                           might cross a quadword boundary.

                           The TRUSTED_SHORT_ALIGNMENT option
                           indicates that the compiler should assume
                           any datatype accessed through a pointer
                           is naturally aligned. This generates the
                           fastest code, but can silently generate
                           the wrong results when an unaligned short
                           object crosses a quadword boundary.

                           Note that on I64 systems, the TRUSTED_
                           SHORT_ALIGNMENT option is ignored and
                           should not cause any behavior changes.

                           The NOTRUSTED_SHORT_ALIGNMENT tells the
                           compiler that short objects might not be
                           naturally aligned. The compiler generates
                           slightly larger (and slower) code that
                           gives the correct result, regardless of
                           the actual alignment of the data. This is
                           the default.

                           Note that the NOTRUSTED_SHORT_ALIGNMENT
                           option does not override the __unaligned
                           type qualifier or the /ASSUME=NOALIGNED_
                           OBJECTS option.
    [NO]WHOLE_PROGRAM      Tells the compiler that except for well-
                           behaved library routines, the whole
                           program consists only of the single
                           object module being produced by this
                           compilation. The optimizations enabled
                           by /ASSUME=WHOLE_PROGRAM include all those
                           enabled by /ASSUME=NOPOINTERS_TO_GLOBALS
                           and possibly other optimizations.

                           Note that on I64 systems, the WHOLE_
                           PROGRAM option is ignored and should not
                           cause any behavior changes.

                           The default is /ASSUME=NOWHOLE_PROGRAM.

 2.5 - /CHECK

       /CHECK
       /CHECK[=([NO]UNINITIALIZED_VARIABLES)] (Alpha only)
       /NOCHECK (D)

    Use this qualifier as a debugging aid.

    Use /CHECK=UNINITIALIZED_VARIABLES to initialize all automatic
    variables to the value 0x7ff580057ff58005. This value is a
    floating NaN and, if used, causes a floating-point trap. If used
    as a pointer, this value is likely to cause an ACCVIO.

    Note that on I64 systems, /CHECK=UNINITIALIZED_VARIABLES emits a
    warning and is ignored.

 2.6 - /COMMENTS

       /COMMENTS
       /COMMENTS[=option]
       /COMMENTS=SPACE (D)
       /NOCOMMENTS

    Specifies whether comments appear in preprocessor output files.
    If comments do not appear, this qualifier specifies what replaces
    them. The options are:

    Option Usage

    AS_IS  Specifies that the comment appear in the output file. This
           is the default if you use the /COMMENTS qualifier without
           specifying an option.
    SPACE  Specifies that a single space replaces the comment in the
           output file. This is the default if you do not specify the
           /COMMENTS qualifier at all.

    Specifying /NOCOMMENTS tells the preprocessor that nothing
    replaces the comment in the output file. This may result in
    inadvertent token pasting.

    The preprocessor may replace a comment at the end of a line
    or replace a line by itself with nothing, even if you specify
    /COMMENTS=SPACE. Specifying /COMMENTS=SPACE cannot change the
    meaning of the program.

 2.7 - /DEBUG

       /DEBUG
       /DEBUG[=(option[,...])]
       /DEBUG=(TRACEBACK,NOSYMBOLS) (D)
       /NODEBUG

    Requests that information be included in the object module for
    use with the OpenVMS Debugger. You can select the following
    options:

    Option          Usage

    ALL             Includes all possible debugging
                    information. /DEBUG=ALL is equivalent to
                    /DEBUG=(TRACEBACK,SYMBOLS), which on I64
                    systems is equivalent to /DEBUG=(TRACEBACK,
                    SYMBOLS=NOBRIEF).
    NONE            Excludes all debugging information.
                    This option is equivalent to specifying
                    /NODEBUG, which is equivalent to
                    /DEBUG=(NOTRACEBACK,NOSYMBOLS).
    NOSYMBOLS       Turns off symbol generation
    SYMBOLS         Generates symbol-table records. On I64
                    systems, /DEBUG= SYMBOLS is equivalent to
                    /DEBUG=SYMBOLS=BRIEF. On Alpha systems,
                    /DEBUG=SYMBOLS is effectively equivalent to
                    /DEBUG=NOBRIEF.
    SYMBOLS=BRIEF   Generates debug information with unreferenced
    (I64 only)      labels and types pruned out to produce smaller
                    object sizes. On Alpha systems, BRIEF is ignored.
    SYMBOLS=NOBRIEF Generates complete debug information. On Alpha
    (I64 only)      systems, the NOBRIEF keyword is ignored, but you
                    still get complete debug information.
    NOTRACEBACK     Excludes traceback records. This option is
                    equivalent to specifying /NODEBUG and is used
                    to avoid generating extraneous information from
                    thoroughly debugged program modules.
    TRACEBACK       Includes only traceback records. This option
                    is the default if you do not specify the /DEBUG
                    qualifier on the command line.

    On Alpha systems /DEBUG is equivalent to
    /DEBUG=(TRACEBACK,SYMBOLS).

    On I64 systems /DEBUG is
    equivalent to /DEBUG=(TRACEBACK,SYMBOLS), which is equivalent
    to /DEBUG=(TRACEBACK,SYMBOLS=BRIEF).

 2.8 - /DEFINE

       /DEFINE
       /DEFINE=(identifier[=definition][,...])
       /NODEFINE (D)

    Performs the same function as the #define preprocessor
    directive. That is, /DEFINE defines a token string or macro to
    be substituted for every occurrence of a given identifier in the
    program.

    DCL converts all input to uppercase unless it is enclosed in
    quotation marks.

    The simplest form of a /DEFINE definition is as follows:

     /DEFINE=true

    This results in a definition like the one that would result from
    the following definition:

     #define TRUE 1

    When more than one /DEFINE is present on the CXX command line or
    in a single compilation unit, only the last /DEFINE is used.

    When both /DEFINE and /UNDEFINE are present on a command line,
    /DEFINE is evaluated before /UNDEFINE.

 2.9 - /DEFINE

       /DEFINE=__FORCE_INSTANTIATIONS (Alpha only)
       /NODEFINE=__FORCE_INSTANTIATIONS (D)

    Forces the standard library template preinstantiations to be
    created in the user's repository. Normally these instantiations
    are suppressed because the library already contains them.

    On I64 systems, defining __FORCE_INSTANTIATIONS has no effect.

 2.10 - /DEFINE

       /DEFINE=__[NO_]USE_STD_IOSTREAM
       /DEFINE=__NO_USE_STD_IOSTREAM (D)

    Use or do not use the standard iostreams. Specifying
    /DEFINE=__USE_STD_IOSTREAM forces the inclusion of the ANSI
    standard version of the iostream header file. This is the default
    in STRICT_ANSI mode. Otherwise, the pre-standard AT&T-compatible
    version of iostreams is used.

 2.11 - /DIAGNOSTICS

       /DIAGNOSTICS
       /DIAGNOSTICS[=file-spec]
       /NODIAGNOSTICS (D)

    Creates a file containing compiler diagnostic messages. The
    default file extension for a diagnostics file is .DIA. The
    diagnostics file is used with the DEC Language-Sensitive
    Editor (LSE). To display a diagnostics file, enter the command
    REVIEW/FILE=file-spec while in LSE.

 2.12 - /DISTINGUISH_NESTED_ENUMS

       /DISTINGUISH_NESTED_ENUMS
       /NODISTINGUISH_NESTED_ENUMS (D)

    Causes the compiler, when forming a mangled name, to include the
    name of any enclosing classes within which an enum is nested,
    thereby preventing different functions from receiving the same
    mangled name.

    This qualifier has no meaning on I64 systems because it modifies
    the behavior of programs compiled with /MODEL=ARM, and that model
    is not supported on I64 systems.

 2.13 - /ENDIAN

       /ENDIAN
       /ENDIAN={BIG | LITTLE}
       /ENDIAN=LITTLE (D)

    Controls whether big or little endian ordering of bytes is
    carried out in character constants.

 2.14 - /ERROR_LIMIT

       /ERROR_LIMIT
       /ERROR_LIMIT[=number]
       /ERROR_LIMIT=30 (D)
       /NOERROR_LIMIT

    Limits the number of error-level diagnostic messages that are
    acceptable during program compilation. Compilation terminates
    when the limit (number) is exceeded. /NOERROR_LIMIT specifies
    that there is no limit on error messages.

    The default is /ERROR_LIMIT=30, which specifies that compilation
    terminates after issuing 30 error messages.

 2.15 - /EXCEPTIONS

       /EXCEPTIONS
       /EXCEPTIONS=CLEANUP (D)
       /EXCEPTIONS=NOCLEANUP (Alpha only)
       /EXCEPTIONS=EXPLICIT (D)
       /EXCEPTIONS=IMPLICIT (Alpha only)
       /NOEXCEPTIONS

    Controls whether support for C++ exceptions is enabled or
    disabled. C++ exceptions are enabled by default (equivalent
    to /EXCEPTIONS=CLEANUP). When C++ exceptions are enabled, the
    compiler generates code for throw expressions, try blocks, and
    catch statements. The compiler also generates special code for
    main programs so that the terminate() routine is called for
    unhandled exceptions. You can select from the following options:

    CLEANUP   Generate cleanup code for automatic objects. When an
              exception is handled at run-time and control passes
              from a throw-point to a handler, call the destructors
              for all automatic objects that were constructed because
              the try-block containing the handler was entered.
    NOCLEANUP Do not generate cleanup code. Using this option can
    (Alpha    reduce the size of your executable when you want to
    only)     throw and handle exceptions and cleanup of automatic
              objects during exception processing is not important
              for your application.

              The NOCLEANUP option is ignored on I64 systems.
    EXPLICIT  Tells the compiler to assume the standard C++ rules
              about exceptions. Catch clauses can catch only those
              exceptions resulting from the evaluation of a throw
              expression within the body of the catch clause's try
              block or from within a procedure called from within the
              catch clause's try block.
    IMPLICIT  On Alpha systems, tells the compiler that an exception
    (Alpha    might be thrown at any time the program is executing
    only)     code within the body of the try block. These exceptions
              might be the result of a throw expression, hardware
              errors, or software errors (such as dereferencing an
              invalid pointer).

              Specifying /EXCEPTIONS=IMPLICIT seriously interferes
              with the compiler's ability to optimize code. When the
              compiler optimizes a function, it must ensure that the
              values of all variables after an exception is caught
              remain the same as they were at the point where the
              exception was throw. The optimizer is therefore limited
              in its ability to rearrange stores and expressions that
              might cause an exception to be thrown.

              With /EXCEPTIONS=EXPLICIT, this is not a serious
              restriction, because the compiler cannot rearrange
              stores and expressions around the code that explicitly
              raises an exception. In implicit exception mode,
              however, almost any code has the potential to cause an
              exception to be thrown, thereby dramatically reducing
              the optimizer's ability to rearrange code.

              Also, if the compiler can determine that no throw
              expressions occur within a try block, it can eliminate
              the exception handling overhead the try block
              introduces, including all code within the catch clauses
              associated with the try block. Because no exceptions
              can occur during the execution of the code within
              the try block, no code within the catch clauses can
              ever be executed. The compiler cannot do this with
              /EXCEPTIONS=IMPLICIT.

              Use /EXCEPTIONS=IMPLICIT if your program converts
              signals to C++ exceptions by calling cxxl$set_
              condition(cxx_exception). Failure to do so may result
              in your code not catching the exceptions produced by
              signals.

    The /NOEXCEPTIONS qualifier disables C++ exceptions as follows:

    1. The compiler issues errors for throw expressions, try blocks,
       and catch statements, but might generate code for these
       constructs.

    2. On Alpha systems, the compiler does not generate cleanup code
       for automatic objects.

    3. The compiler does not generate special code for main programs
       so that the terminate() function is called for unhandled
       exceptions.

    The /EXCEPTIONS qualifer defines the macro __EXCEPTIONS.

 2.16 - /EXPORT_SYMBOLS

       /EXPORT_SYMBOLS=(OPTIONS_FILE=<name>
    [,EXCLUDE=<list of images>]
    [,export_option]
    [,NOTEMPLATES]) (I64 only)

    Creating OpenVMS shareable images that contain C++ code has long
    been a problem for users. When building a shareable image, you
    must specify a list of exported global symbols. For C++ code,
    determining this list can be very difficult for the following
    reasons:

    o  Required C++ name mangling makes it difficult to know the name
       of the external symbol created for a C++ name.

    o  OpenVMS CRC encoding (to 31 characters) further complicates
       mapping source names to object names.

    o  Certain C++ constructs require compiler-generated names to be
       created and exported.

    To help solve the problem, the HP C++ compiler provides the
    /EXPORT_SYMBOLS qualifier and __declspec(dllexport) declaration
    modifier.

    The default file extension for the OPTIONS_FILE <name> is .OPT.

    If the file exists, the compiler appends to it. If the file does
    not exist, the compiler creates it.

    The output for the compilation is:

          !
          ! Entries added for <module>
          !
          <symbol vector>
          <symbol vector>
          .
          .
          .

    The output file is suitable input to a linker options file that
    can be used to build a shareable image containing the compiled
    object.

    The format of each <symbol vector> is:

       SYMBOL_VECTOR=(<global name>={DATA | PROCEDURE}) ! <comment field>

    The <comment field> format is:

       <unmangled name> [<promoted static flag>] [<class information>]

    The <promoted static flag> is one of the following:

       *PSDM* - for promoted static data members
       *PTSDM* - for promoted template static data members

    The <promoted static flag> is output whenever the symbol is a
    promoted local static or a promoted template static data member.
    This is important because these variables, while declared static,
    actually become global symbols when compiled.

    The <class information> field is present if the symbol is a
    member of a class. It contains the name of the class.

                                  NOTES

       o  When /EXPORT_SYMBOLS is specified, an object file must
          also be generated. So /EXPORT_SYMBOLS cannot be used with
          /NOOBJ, /PREPROCESS_ONLY, or any other qualifier that
          prevents the creation of an object file.

       o  When the options file already exists, the compiler reads
          all the symbols that are listed there. If the current
          compilation also defines one of those symbols, that
          symbol will not be added to the options file. This is
          necessary to prevent SYMVALRDEF warnings from the linker.

       o  When the compiler reads the existing file, it treats
          SYMBOL_VECTOR directives that are in comments (of the
          form !SYMBOL_VECTOR...) as if they were not commented.
          In this way, if a user does not want to export a symbol,
          placing it in comments will prevent the compiler from
          emitting a directive for that symbol when it compiles
          other sources that might also define the symbol.

       o  The symbols placed in the options file are a subset
          of the symbols defined in the output object file. The
          export_option value controls exactly which symbols are
          placed there. There are three choices:

          Export_
          option
          Value     Usage

          ALL       Place all symbols suitable for placement in
                    a sharable image into the options file. The
                    compiler knows that certain symbols are not
                    suited for placement in a shareable image
                    and excludes them from the options file.
                    Some examples are certain compiler-generated
                    constructor/destructor jackets and symbols in
                    the unnamed namespace.
          EXPLICIT  Place only those symbols marked with the
                    __declspec(dllexport) declaration modifier
                    into the options file.
          AUTOMATIC(If the compiler processes a
                    __declspec(dllexport), then act as if EXPLICIT
                    was specified. If the compiler does not
                    process a __declspec(dllexport), then act
                    as if ALL was specified.

       o  The EXCLUDE option of the /EXPORT_SYMBOLS qualifier
          can be used to specify a list of shareable images. The
          compiler searches these images for any symbols that it
          might want to place in the output options file. If it
          finds the symbol in the image, then that symbol will not
          be put into the options file.

       o  The NOTEMPLATES option can be used to control
          the emission of symbols associated with template
          instantiations. Specifying this option causes the
          compiler to suppress symbols created by template
          instantiation. This includes instantiations of class
          templates, its data members and member functions, and
          instantiations of function templates. This option could
          be used to avoid multiple definition diagnostics from the
          linker if multiple sharable images might be instantiating
          (and exporting) the same template symbols. Symbols
          marked with __declspec(dllexport) still get exported.
          This option has no effect on symbols from template
          specializations. Note that while this option might
          make the sharable images smaller by not exporting the
          template symbols, the executable image that links with
          these sharable images might be larger because it will
          contain the instantiated template symbols.

    Because shareable images almost always contain a number of
    objects, the commands for creating the options file the first
    time might be:

    $ DELETE options_file.OPT;*
    $ CXX SOURCE1/EXPORT_SYMBOLS=OPTIONS_FILE=options_file
    $ CXX SOURCE2/EXPORT_SYMBOLS=OPTIONS_FILE=options_file
    $ CXX SOURCE3/EXPORT_SYMBOLS=OPTIONS_FILE=options_file
       .
       .
       .
    $ CXX SOURCEn/EXPORT_SYMBOLS=OPTIONS_FILE=options_file

    Where SOURCE1 - SOURCEn are the sources for the shareable. After
    the compilations, the options_file.OPT will contain correct
    symbol vector information for the shareable.

    The first time this options file is created, it can be considered
    a candidate options file. It contains all the symbol vector
    entries for all the C++ globals that make sense to export from
    the C++ language point of view. A user can then edit this file to
    exclude (by commenting out) entries that should not be exported,
    based on the design of the library.

    Once an options file is created, it should be maintained for
    input to subsequent compilations. In this way, any new symbols
    caused by a change in the source will be added to the end of the
    compilation. Any existing symbols will not be added, as described
    in the NOTES section above. This technique ensures that the order
    of symbols remains unchanged, and that future shared libraries
    are compatible with existing ones.

 2.17 - /EXTERN_MODEL

       /EXTERN_MODEL
       /EXTERN_MODEL=option
       /EXTERN_MODEL=RELAXED_REFDEF (D)

    In conjunction with the /SHARE_GLOBALS qualifier, controls the
    initial extern model of the compiler. Conceptually, the compiler
    behaves as if the first line of the program being compiled was a
    #pragma extern_model directive with the model and psect name, if
    any, specified by the /EXTERN_MODEL qualifier and with the SHR or
    NOSHR keyword specified by the /SHARE_GLOBALS qualifier.

    For example, assume the command line contains the following
    qualifier:

    /EXTERN_MODEL=STRICT_REFDEF="MYDATA"/NOSHARE

    The compiler acts as if the program began with the following
    line:

          #pragma extern_model strict_refdef "MYDATA" noshr

    For more information on the various models, see "C++
    Implementation" in the HP C++ User's Guide for OpenVMS Systems.

    The /EXTERN_MODEL qualifier takes the following options, which
    have the same meaning as for the #pragma extern_model directive:

       COMMON_BLOCK
       RELAXED_REFDEF
       STRICT_REFDEF=["NAME"]
       GLOBALVALUE

    The default is RELAXED_REFDEF.

    Use of an /EXTERN_MODEL value other than RELAXED_REFDEF should
    be limited to compilations that either declare only POD (Plain
    Old Data) objects, or that carefully use the extern_model (and/or
    environment) #pragma directives to ensure that declarations of
    non-POD objects appear only in source that is subject to the
    default extern_model of relaxed_refdef.

 2.18 - /FIRST_INCLUDE

       /FIRST_INCLUDE
       /FIRST_INCLUDE=(file[, . . . ])
       /NOFIRST_INCLUDE (D)

    Includes the specified files before any source files. This
    qualifier corresponds to the Tru64 UNIX -FI switch.

    When /FIRST_INCLUDE=file is specified, file is included in the
    source as if the line before the first line of the source were:

    #include "file"

    If more than one file is specified, the files are included in
    their order of appearance on the command line.

    This qualifier is useful if you have command lines to pass to the
    C compiler that are exceeding the DCL command-line length limit.
    Using the /FIRST_INCLUDE qualifier can help solve this problem by
    replacing lengthy /DEFINE and /WARNINGS qualifiers with #define
    and #pragma message preprocessor directives placed in a /FIRST_
    INCLUDE file.

    The default is /NOFIRST_INCLUDE.

 2.19 - /FLOAT

       /FLOAT
       /FLOAT=option
       /FLOAT=G_FLOAT (Alpha only) (D)
       /FLOAT=IEEE_FLOAT (I64 only) (D)

    Controls the format of floating-point variables. The options are:

    Option          Usage

    D_FLOAT         double variables are represented in VAX D_
                    floating format. float variables are represented
                    in VAX F_floating format. The __D_FLOAT macro is
                    predefined.
    G_FLOAT         double variables are represented in VAX G_
                    floating format. float variables are represented
                    in VAX F_floating format. The __G_FLOAT macro is
                    predefined.
    IEEE_FLOAT      float and double variables are represented in
                    IEEE floating-point format (S_float and T_
                    float, respectively). The __IEEE_FLOAT macro
                    is predefined. Use the /IEEE_MODE qualifier for
                    controlling the handling of IEEE exceptional
                    values.

    On Alpha systems, the default is /FLOAT=G_FLOAT.

    On I64 systems, the default is /FLOAT=IEEE_FLOAT.

    See the HP C++ User's Guide for OpenVMS Systems for additional
    information on floating-point representation on I64 and Alpha
    systems.

 2.20 - /GRANULARITY

       /GRANULARITY
       /GRANULARITY=option
       /GRANULARITY=QUADWORD (D)

    Controls the size of shared data in memory that can be safely
    accessed from different threads. The possible size values are
    BYTE, LONGWORD, and QUADWORD.

    Specifying BYTE allows single bytes to be accessed from different
    threads sharing data in memory without corrupting surrounding
    bytes. This option will slow runtime performance.

    Specifying LONGWORD allows naturally aligned 4-byte longwords
    to be accessed safely from different threads sharing data in
    memory. Accessing data items of 3 bytes or less, or unaligned
    data, may result in data items written from multiple threads
    being inconsistently updated.

    Specifying QUADWORD allows naturally aligned 8-byte quadwords
    to be accessed safely from different threads sharing data in
    memory. Accessing data items of 7 bytes or less, or unaligned
    data, might result in data items written from multiple threads
    being inconsistently updated. This is the default.

 2.21 - /IEEE_MODE

       /IEEE_MODE
       /IEEE_MODE=option
       /IEEE_MODE=FAST (D) (Alpha only)
       /IEEE_MODE=DENORM_RESULTS (D) (I64 only)

    Selects the IEEE floating-point mode to be used if the
    /FLOAT=IEEE_FLOAT qualifier is specified. The options are:

    Option         Usage

    FAST           During program execution, only finite values
                   (no infinities, NaNs, or denorms) are created.
                   Underflows and denormal values are flushed to
                   zero. Exceptional conditions, such as floating-
                   point overflow, divide-by-zero, or use of an IEEE
                   exceptional operand are fatal.
    UNDERFLOW_     Generate infinities and NaNs. Flush denormalized
    TO_ZERO        results and underflow to zero without exceptions.
    DENORM_        Same as the UNDERFLOW_TO_ZERO option, except that
    RESULTS        denorms are generated.
    INEXACT        Same as the DENORM_RESULTS option, except that
                   inexact values are trapped. This is the slowest
                   mode, and is not appropriate for any sort of
                   general-purpose computations.

    On Alpha systems, the default is /IEEE_MODE=FAST.

    On I64 systems, the default is /IEEE_MODE=DENORM_RESULTS.

    The INFINITY and NAN macros defined in <math.h> are available to
    programs compiled with /FLOAT=IEEE and /IEEE_MODE={anything other
    than FAST}.

    On Alpha sytems, the /IEEE_MODE qualifier generally has its
    greatest effect on the generated code of a compilation. When
    calls are made between functions compiled with different /IEEE_
    MODE qualifiers, each function produces the /IEEE_MODE behavior
    with which it was compiled.

    On I64 systems, the /IEEE_MODE qualifier primarily affects
    only the setting of a hardware register at program startup.
    In general, the /IEEE_MODE behavior for a given function is
    controlled by the /IEEE_MODE option specified on the compilation
    that produced the main program: the startup code for the main
    program sets the hardware register according the command-line
    qualifiers used to compile the main program.

    When applied to a compilation that does not contain a main
    program, the /IEEE_MODE qualifier does have some effect: it might
    affect the evaluation of floating-point constant expressions, and
    it is used to set the EXCEPTION_MODE used by the math library for
    calls from that compilation. But the qualifier has no effect on
    the exceptional behavior of floating-point calculations generated
    as inline code for that compilation. Therefore, if floating-point
    exceptional behavior is important to an application, all of its
    compilations, including the one containing the main program,
    should be compiled with the same /IEEE_MODE setting.

    Even on Alpha systems, the particular setting of /IEEE_
    MODE=UNDERFLOW_TO_ZERO has this characteristic: its primary
    effect requires the setting of a runtime status register, and
    so it needs to be specified on the compilation containing the
    main program in order to be effective in other compilations.

    Also see the /FLOAT qualifier.

 2.22 - /IMPLICIT_INCLUDE

       /IMPLICIT_INCLUDE
       /IMPLICIT_INCLUDE (D)
       /NOIMPLICIT_INCLUDE

    /IMPLICIT_INCLUDE enables inclusion of source files as a method
    of finding definitions of template entities. By default it is
    enabled for normal compilation, and disabled for preprocessing
    only. The search rules for finding template definition files is
    the same as for include files.

    /NOIMPLICIT_INCLUDE disables inclusion of source files as a
    method of finding definitions of template entities. You might
    want to use this option in conjunction with the /STANDARD=MS
    command line option, to match more closely the behavior on
    Microsoft C++.

 2.23 - /INCLUDE_DIRECTORY

       /INCLUDE_DIRECTORY
       /INCLUDE_DIRECTORY=(place[,...])
       /NOINCLUDE_DIRECTORY (D)

    Provides an additional level of search for user-defined include
    files. Each pathname argument can be either a logical name or
    a legal UNIX style directory in a quoted string. The default is
    /NOINCLUDE_DIRECTORY.

    The /INCLUDE_DIRECTORY qualifier provides functionality similar
    to the -I option of the cxx command on Tru64 UNIX systems.
    This qualifier allows you to specify additional locations to
    search for files to include. Putting an empty string in the
    specification prevents the compiler from searching any of the
    locations it normally searches but directs it to search only
    in locations you identify explicitly on the command line with
    the /INCLUDE_DIRECTORY And /LIBRARY qualifiers (or by way of
    the specification of the primary source file, depending on the
    /NESTED_INCLUDE_DIRECTORY qualifier).

    The basic order for searching depends on the form of the header
    name (after macro expansion), with additional aspects controlled
    by other command line qualifiers as well as the presence or
    absence of logical name definitions. The valid possibilities
    for names are as follows:

    o  Enclosed in quotes. For example: "stdio.h"

    o  Enclosed in angle brackets. For example: <stdio.h>

    Unless otherwise defined, searching a location means that the
    compiler uses the string specifying the location as the default
    file specification in a call to an RMS system service (that is,
    a $SEARCH/$PARSE) with a primary file specification consisting
    of the name in the #include (without enclosing delimiters). The
    search terminates successfully as soon as a file can be opened
    for reading.

    Specifying a null string in the /INCLUDE qualifier causes the
    compiler to do a non-standard search. This search path is as
    follows:

    1. The current directory (quoted form only)

    2. Any directories specified in the /INCLUDE qualifier

    3. The directory of the primary input file

    4. Text libraries specified on the command line using /LIBRARY

    For standard searches, the search order is as follows:

    1. Search the current directory (directory of the source
       being processed). If angle-bracket form, search only if no
       directories are specified with /INCLUDE_DIRECTORY.

    2. Search the locations specified in the /INCLUDE_DIRECTORY
       qualifier (if any).

    3. If CXX$SYSTEM_INCLUDE is defined as a logical name, search
       CXX$SYSTEM_INCLUDE:.HXX or just CXX$SYSTEM_INCLUDE:.,
       depending on the qualifier /ASSUME=NOHEADER_TYPE_DEFAULT.
       If nothing is found, go to step 6.

    4. If CXX$LIBRARY_INCLUDE is defined as a logical name,
       CXX$LIBRARY_INCLUDE:.HXX or CXX$LIBRARY_INCLUDE:., depending
       on the qualifier /ASSUME=NOHEADER_TYPE_DEFAULT. If nothing is
       found, go to step 6.

    5. If /ASSUME=HEADER_TYPE_DEFAULT is not specified, search the
       default list of locations for plain-text copies of compiler
       header files as follows:

          SYS$COMMON:[CXX$LIB.INCLUDE.CXXL$ANSI_DEF]
          SYS$COMMON:[CXX$LIB.INCLUDE.DECC$RTLDEF_HXX].HXX
          SYS$COMMON:[DECC$LIB.INCLUDE.DECC$RTLDEF].H
          SYS$COMMON:[DECC$LIB.INCLUDE.SYS$STARLET_C].H

       If /ASSUME=HEADER_TYPE_DEFAULT is specified, search the
       default list of locations for plain-text copies of compiler
       header files as follows:

          SYS$COMMON:[CXX$LIB.INCLUDE.DECC$RTLDEF_HXX].HXX
          SYS$COMMON:[DECC$LIB.INCLUDE.DECC$RTLDEF].H
          SYS$COMMON:[DECC$LIB.INCLUDE.SYS$STARLET_C].H
          SYS$COMMON:[CXX$LIB.INCLUDE.CXXL$ANSI_DEF]

    6. Search the directory of the primary input file.

    7. If quoted form, and CXX$USER_INCLUDE is defined as a logical
       name, search CXX$USER_INCLUDE:.HXX or CXX$USER_INCLUDE:.,
       depending on the /ASSUME=NOHEADER_TYPE_DEFAULT qualifier.

    8. Search the text libraries. Extract the simple file name and
       file type from the #include specification, and use them to
       determine a module name for each text library. There are three
       forms of module names used by the compiler:

       1. type stripped:

          The file type will be removed from the include file
          specification to form a library module name. Examples:

          #include        Module name "FOO"
          "foo.h"
          #include        Module name "FOO"
          "foo"
          #include        Module name "FOO"
          "foo"

       2. type required:

          The file type must be a part of the file name. Examples:

          #include        Module name "FOO.H"
          "foo.h"
          #include        Module name "FOO."
          "foo"
          #include        Module name "FOO."
          "foo"

       3. type optional:

          First an attempt is made to find a module with the type
          included in the module name. If this is unsuccessful, an
          attempt is made with the type stripped from the module
          name. If this is unsuccessful, the search moves on to the
          next library.

       If /ASSUME=HEADER_TYPE_DEFAULT is specified, the following
       text libraries are searched in this order:

          Libraries specified on the command line with the /LIBRARY
          qualifier (all files, type stripped)
          CXX$TEXT_LIBRARY (all files, type stripped)
          DECC$RTLDEF (H files and unspecified files, type stripped)
          SYS$STARLET_C (all files, type stripped)
          CXXL$ANSI_DEF (unspecified files, type stripped)

       Otherwise, these text libraries are searched in this order:

          Libraries specified on the command line with the /LIBRARY
          qualifier (all files, type optional)
          CXX$TEXT_LIBRARY (all files, type optional)
          CXXL$ANSI_DEF (all files, type required)
          DECC$RTLDEF (H files and unspecified files, type stripped)
          SYS$STARLET_C (all files, type stripped)

       Two text library search examples (stop when something is
       found):

       Example 1

       #include "foo"

       1. For each library specified via the /LIBRARY qualifier:

             - Look for "FOO."
             - Look for "FOO"

       2. Look for "FOO." in CXX$TEXT_LIBRARY

       3. Look for "FOO" in CXX$TEXT_LIBRARY

       4. Look for "FOO." in CXXL$ANSI_DEF (Do not look for "FOO"
          because the type is required as part of the module name)

       5. Look for "FOO" in DECC$RTLDEF (not "FOO." because the type
          must not be part of the module name)

       6. Look for "FOO" in SYS$STARLET_C (not "FOO." because the
          type must not be part of the module name)

       Example 2

       #include "foo.h"

       1. For each library specified via the /LIBRARY qualifier:

             - Look for "FOO.H"
             - Look for "FOO"

       2. Look for "FOO.H" in CXX$TEXT_LIBRARY

       3. Look for "FOO" in CXX$TEXT_LIBRARY

       4. Look for "FOO.H" in CXXL$ANSI_DEF (Do not look for "FOO"
          because the type is required as part of the module name)

       5. Look for "FOO" in DECC$RTLDEF (not "FOO.H" because the type
          must not be part of the module name)

       6. Look for "FOO" in SYS$STARLET_C (not "FOO.H" because the
          type must not be part of the module name)

       7. If neither CXX$LIBRARY_INCLUDE nor CXX$SYSTEM_INCLUDE is
          defined as a logical name, then search SYS$LIBRARY:.HXX.

 2.24 - /L_DOUBLE_SIZE

       /L_DOUBLE_SIZE
       /L_DOUBLE_SIZE=option
       /L_DOUBLE_SIZE=128 (D)

    Determines how the compiler interprets the long double type. The
    qualifier options are 64 and 128.

    Specifying /L_DOUBLE_SIZE=64 treats all long double references
    as G_FLOAT, D_FLOAT, or T_FLOAT, depending on the value of the
    /FLOAT qualifier. Specifying /L_DOUBLE_SIZE=64 also defines the
    macro __X_FLOAT=0.

    Note: The /L_DOUBLE_SIZE=64 option is not available on I64
    systems. If it is specified, the compiler issues a warning
    message and uses /L_DOUBLE_SIZE=128.

    Specifying /L_DOUBLE_SIZE=128 treats all long double references
    as X_FLOAT. The /L_DOUBLE_SIZE=128 option also defines the macro
    __X_FLOAT=1. This is the default.

 2.25 - /LIBRARY

    Indicates that the associated input file is a text library
    containing source text modules specified in #include directives.
    The compiler searches the specified library for all #include
    module names that are not enclosed in angle brackets or quotation
    marks. The name of the library must be concatenated with
    the file specification using a plus sign. For example: CXX
    DATAB/LIBRARY+APPLICATION

 2.26 - /LINE_DIRECTIVES

       /LINE_DIRECTIVES
       /LINE_DIRECTIVES (D)
       /NOLINE_DIRECTIVES

    Controls whether #line directives appear in preprocessed output
    files.

 2.27 - /LIST

       /LIST
       /LIST[=file-spec] (Batch default)
       /NOLIST (Interactive default)

    Controls whether a listing file is produced. The default output
    file extension is .LIS.

 2.28 - /MACHINE_CODE

       /MACHINE_CODE
       /NOMACHINE_CODE (D)

    Controls whether the listing produced by the compiler includes
    the machine-language code generated during the compilation. If
    you use this qualifier you also need to use the /LIST qualifier.
    On Alpha systems, machine-language code is not added to the
    listing file when object-file generation is disabled (using the
    /NOOBJECT qualifier).

 2.29 - /MAIN

       /MAIN=POSIX_EXIT
       /MAIN=POSIX_EXIT
       /NOMAIN (D)

    Directs the compiler to call __posix_exit instead of exit when
    returning from main.

 2.30 - /MEMBER_ALIGNMENT

       /MEMBER_ALIGNMENT
       /MEMBER_ALIGNMENT (D)
       /NOMEMBER_ALIGNMENT

    Directs the compiler to naturally align data structure members.
    This means that data structure members are aligned on the next
    boundary appropriate to the type of the member, rather than on
    the next byte. For instance, a long variable member is aligned on
    the next longword boundary; a short variable member is aligned on
    the next word boundary.

    Any use of the #pragma member_alignment or #pragma nomember_
    alignment directives within the source code overrides the setting
    established by this qualifier. Specifying /NOMEMBER_ALIGNMENT
    causes data structure members to be byte-aligned (with the
    exception of bit-field members).

 2.31 - /MMS_DEPENDENCIES

       /MMS_DEPENDENCIES
       /MMS_DEPENDENCIES[=(option[,option)]]
       /NOMMS_DEPENDENCIES (D)

    Instructs the compiler to produce a dependency file. The format
    of the dependency file is as follows:

    object_file_name:<tab><source file name>
    object_file_name:<tab><full path to first include file>
    object_file_name:<tab><full path to second include file>

    You can specify none, one, or both of the following qualifier
    options:

    FILE[=filespec]    Specifies where to save the dependency file.
                       The default file extension for a dependency
                       file is .mms. Other than using a different
                       default extension, this qualifier uses the
                       same procedure that /OBJECT and /LIST use for
                       determining the name of the output file.
    SYSTEM_INCLUDE_    Specifies whether to include dependency
    FILES              information about system include files
                       (that is, those included with #include
                       <filename>). The default is to include
                       dependency information about system include
                       files.

 2.32 - /MODEL

       /MODEL (Alpha only)
       /MODEL={ANSI | ARM}
       /MODEL=ARM (D)

    On Alpha systems, determines the layout of C++ classes, name
    mangling, and exception handling.

    On I64 systems, the default (and only) object model & demangling
    scheme used is the I64 Application Binary Interface (ABI). The
    compiler accepts the /MODEL qualifier, but it has no effect.

    On Alpha systems, /MODEL=ARM is the default and generates objects
    that are link compatible with all releases prior to HP C++
    version 6.3, and with all objects compiled with the /MODEL=ARM
    qualifier in releases of HP C++ Version 6.3 or later. Specifying
    this option defines the macro __MODEL_ARM.

    The /MODEL=ANSI qualifier supports the complete ISO/ANSI C++
    specification, including distinct name mangling for templates.
    The ANSI model also reduces the size of C++ non-POD class
    objects. Note that this option generates objects that are not
    compatible with all prior and future releases of HP C++, or with
    objects compiled using the /MODEL=ARM qualifier.

    If you specify the /MODEL=ANSI qualifier, you must recompile
    and relink (using CXXLINK/MODEL=ANSI) your entire application,
    including libraries. Specifying this option defines the macro
    __MODEL_ANSI.

 2.33 - /NAMES

       /NAMES
       /NAMES=(option1,option2)
       /NAMES=(UPPERCASE,TRUNCATED) (D)

    Option1 converts all definitions and references of external
    symbols and psects to the case specified. Option1 values are:

    Option       Usage

    UPPERCASE    Converts to uppercase.
    AS_IS        Leaves the case as specified in the source.

    Option2 controls whether or not external names greater than 31
    characters get truncated or shortened. Option2 values are:

    Option             Usage

    /NAMES=TRUNCATED   Truncates long external names to the first 31
    (default)          characters.
    /NAMES=SHORTENED   Shortens long external names.

                       A shortened name consists of the first 23
                       characters of the name followed by a 7-
                       character Cyclic Redundancy Check (CRC)
                       computed by looking at the full name, and
                       then a "$".

    The default is /NAMES=(UPPERCASE,TRUNCATED).

                                   NOTE

       The I64 C++ compiler has some additional encoding rules that
       are applied to symbol names after the ABI name mangling
       is determined. All symbols with C++ linkage have CRC
       encodings added to the name, are uppercased and shorten to
       31 characters if necessary. Since the CRC is computed before
       the name is uppercased, the symbol name is case-sensitive
       even though the final name is in uppercase. /NAMES=AS_IS and
       /NAMES=UPPER are not applicable to these symbols.

       All symbols without C++ linkage will have CRC encodings
       added if they are longer then 31 characters and
       /NAMES=SHORTEN is specified. Global variables with C++
       linkage are treated as if they have non-C++ linkage for
       compatibility with C and older compilers.

 2.34 - /NESTED_INCLUDE_DIRECTORY

       /NESTED_INCLUDE_DIRECTORY
       /NESTED_INCLUDE_DIRECTORY[=option]
       /NESTED_INCLUDE_DIRECTORY=INCLUDE_FILE (D)

    Controls the first step in the search algorithm the compiler
    uses when looking for files included using the quoted form of
    the #include preprocessing directive: #include "file-spec" The
    /NESTED_INCLUDE_DIRECTORY qualifier has the following options:

    Option     Usage

    PRIMARY_   Directs the compiler to search the default file type
    FILE       for headers using the context of the primary source
               file. This means that only the file type (".H" or ".")
               is used for the default file-spec but, in addition,
               the chain of "related file-specs" used to maintain
               the sticky defaults for processing the next top-level
               source file is applied when searching for the include
               file.
    INCLUDE_   Directs the compiler to search the directory
    FILE       containing the file in which the #include directive
               itself occurred. The meaning of "directory containing"
               is: the RMS "resultant string" obtained when the file
               in which the #include occurred was opened, except that
               the filename and subsequent components are replaced
               by the default file type for headers (".H", or just
               "." if /ASSUME=NOHEADER_TYPE_DEFAULT is in effect).
               The "resultant string" will not have translated any
               concealed device logical.
    NONE       Directs the compiler to skip the first step of
               processing #include "file.h" directives. The compiler
               starts its search for the include file in the
               /INCLUDE_DIRECTORY directories.

    For more information on the search order for included files, see
    the /INCLUDE_DIRECTORY qualifier.

 2.35 - /OBJECT

       /OBJECT
       /OBJECT[=file-spec]
       /OBJECT=.OBJ (D)
       /NOOBJECT

    Controls whether the compiler produces an output object module.
    The default output file extension is .OBJ.

    Note that the /OBJECT qualifier has no impact on the output file
    of the /MMS_DEPENDENCIES qualifier.

 2.36 - /OPTIMIZE

       /OPTIMIZE
       /OPTIMIZE[=option]
       /OPTIMIZE=(LEVEL=4,INLINE=AUTOMATIC,INTRINSICS,UNROLL=0,
    NOOVERRIDE_LIMITS,TUNE=GENERIC) (D)
       /NOOPTIMIZE

    Controls the level of code optimization that the compiler
    performs. The options are as follows:

    Option        Usage

    LEVEL=n       Selects the level of code optimization. Specify
                  an integer from 0 (no optimization) to 5 (full
                  optimization).
    [NO]INLINE    Provides inline expansion of functions that yield
                  optimized code when they are expanded. You can
                  specify one of the following keywords to control
                  inlining:
                  NONE      No inlining is done, even if requested by
                            the language syntax.
                  MANUAL    Inlines only those function calls for
                            which the program explicitly requests
                            inlining.
                  AUTOMATIC Inlines all of the function calls in
                            the MANUAL category, plus additional
                            calls that the compiler determines are
                            appropriate on this platform. On Alpha
                            systems, the heuristics for AUTOMATIC
                            are similar to those for SIZE; on I64
                            systems, they are more like those for
                            SPEED. AUTOMATIC is the default.
                  SIZE      Inlines all of the function calls in
                            the MANUAL category plus any additional
                            calls that the compiler determines would
                            improve run-time performance without
                            significantly increasing the size of the
                            program.
                  SPEED     Performs more aggressive inlining for
                            run-time performance, even when it might
                            significantly increase the size of the
                            program.
                  ALL       Inlines every call that can be inlined
                            while still generating correct code.
                            Recursive routines, however, will not
                            cause an infinite loop at compile time.
                            On I64 systems, ALL is treated as if SIZE
                            had been specified.

                            Note that /OPT=INLINE=ALL is not
                            recommended for general use, because
                            it performs very aggressive inlining and
                            can cause the compiler to exhaust virtual
                            memory or take an unacceptably long time
                            to compile.
    [NO]OVERRIDE_ Controls whether or not the compiler uses certain
    LIMITS (I64   built-in limits on the size and complexity of
    only)         a function to "throttle back" the amount of
                  optimization performed in order to reduce the
                  likelihood that the compiler will use excessive
                  memory resources or CPU time attempting to optimize
                  the code.

                  The default is NOOVERRIDE_LIMITS, which means that
                  when compiling a function that has an unusually
                  large number of basic blocks, live variables, or
                  other properties that tend to cause the optimizer
                  to use extra resources, the informational message
                  OPTLIMEXC might be issued to notify you that
                  optimization has been reduced to avoid excessive
                  resource use.

                  You can choose to ignore this message or disable
                  it (the message is not issued on compilations with
                  optimization disabled).

                  Or you can specify /OPTIMIZE=OVERRIDE_LIMITS, which
                  instructs the compiler to not check the limits and
                  to attempt full optimization no matter how large or
                  complex the function, knowing that the compilation
                  might exhaust memory or seem to be in a loop.

                  If using /OPTIMIZE=OVERRIDE_LIMITS does result
                  in excessive resource use, you are sure that
                  the compiler process has plenty of memory quota
                  available, you are convinced that the compilation
                  does not contain any unusually large or complex
                  functions, and you can provide complete source
                  code, then you might want to contact your support
                  channel to see if there is a problem in the
                  compiler causing it to use more resources than
                  it should for the particular compilation at hand.
    TUNE          Specifies the preferred processor for execution.
                  This option makes some decisions preferentially
                  for the specified processor (for example, for code
                  scheduling). Note that code valid only for the
                  specified processor can be generated. However,
                  parallel code can be generated for processors down
                  to the specified architecture level if necessary;
                  that is, tuning specifies the preferred target,
                  while architecture level specifies a lower boundary
                  on available processor features.

                  For example, /ARCHITECTURE=EV56/OPTIMIZE=TUNE=EV6
                  specifies that the code does not need to run on
                  a processor older than an EV56, and that the code
                  will probably run on an EV6. The generated code
                  will run on all EV56 and later systems without any
                  emulation. The code might have run-time selected
                  conditional regions specifically for EV6. Also,
                  note that because emulation is provided, the code
                  should run, but potentially at very significantly
                  reduced speed, on pre-EV56 processors.

                  The options for TUNE are the same as the options
                  for /ARCH. You can specify one of the following
                  keywords:
                  GENERIC        Selects instruction tuning
                                 that is appropriate for all
                                 implementations of the operating
                                 system architecture. This option is
                                 the default.
                  HOST           Selects instruction tuning that is
                                 appropriate for the machine on which
                                 the code is being compiled.
                  ITANIUM2       Selects instruction tuning for the
                  (I64 only)     Intel Itanium 2 processor.
                  EV4 (Alpha     Selects instruction tuning for the
                  only)          21064, 21064A, 21066, and 21068
                                 implementations of the operating
                                 system architecture.
                  EV5 (Alpha     Selects instruction tuning for
                  only)          the 21164 implementation of the
                                 operating system architecture.
                  EV56 (Alpha    Selects instruction tuning for
                  only)          21164 chip implementations that
                                 use the byte- and word-manipulation
                                 instruction extensions of the Alpha
                                 architecture.

                                 Running programs compiled with the
                                 EV56 keyword might incur emulation
                                 overhead on EV4 and EV5 processors,
                                 but will still run correctly on
                                 OpenVMS Version 7.1 (or later)
                                 systems.
                  PCA56 (Alpha   Selects instruction tuning for the
                  only)          21164PC chip implementation that
                                 uses the byte- and word-manipulation
                                 instruction extensions and
                                 multimedia instruction extensions
                                 of the Alpha architecture.

                                 Programs compiled with the PCA56
                                 keyword might incur emulation
                                 overhead on EV4, EV5, and EV56
                                 processors, but will still run
                                 correctly on OpenVMS Version 7.1
                                 (or later) systems.
                  EV6 (Alpha     Selects instruction tuning for
                  only)          the first-generation 21264
                                 implementation of the Alpha
                                 architecture.
                  EV67 (Alpha    Selects instruction tuning for
                  only)          the second-generation 21264
                                 implementation of the Alpha
                                 architecture.
    [NO]INTRINSICSControls whether certain functions are handled as
                  intrinsic functions without explicitly enabling
                  each of them as an intrinsic through the #pragma
                  intrinsic preprocessor directive.

                  Functions that can be handled as intrinsics are:

                  Main Group - ANSI:

                  abs   atanl  atan2l ceill  cosl  floorf memcpy  sinf

                  atan  atan   ceil   cos    fabs  floorl memmove sinl sin

                  atanf atan2f ceilf  cosf   floor labs   memset  strcpy strlen

                  Main Group - Non-ANSI:

                         alloca  atand2  bzero  sind
                         atand   bcopy   cosd

                  Printf functions:

                         fprintf printf  sprintf

                  Printf non-ANSI:

                         snprintf

                  ANSI math functions that set errno, thereby
                  requiring /ASSUME=NOMATH_ERRNO:

                  acos   asinf  coshl  log   log10f  powl   sqrt   tanf

                  acosf  asinl  exp    logf  log10l  sinh   sqrtf  tanl

                  acosl  cosh   expf   logl  pow     sinhf  sqrtl  tanh tanhl

                  asin   coshf  expl   log10 powf    sinhl  tan    tanhf

                  Non-ANSI math functions that set errno, thereby
                  requiring /ASSUME=NOMATH_ERRNO:

                              log2 tand

                  The /OPTIMZE=INTRINSICS qualifier works with
                  /OPTIMIZE=LEVEL =n and some other qualifiers to
                  determine how intrinsics are handled:

                  o  If the optimization level specified is less than
                     4, the intrinsic-function prototypes and call
                     formats are checked, but normal run-time calls
                     are still made.

                  o  If the optimization level is 4 or higher,
                     intrinsic code is generated.

                  o  Intrinsic code is not generated for math
                     functions that set the errno variable unless
                     /ASSUME=NOMATH_ERRNO is specified. Such math
                     functions, however, do have their prototypes and
                     call formats checked.

                     The default is /OPTIMIZE=INTRINSICS, which turns
                     on this handling.

                     To turn it off, use /NOOPTIMIZE or
                     /OPTIMIZE=NOINTRINSICS.

    UNROLL=n      Controls loop unrolling done by the optimizer.
                  Specify a positive integer to indicate the number
                  of times to unroll loop bodies. If you specify 0
                  or do not supply a value, the optimizer determines
                  its own unroll amount. The default is UNROLL=0.
                  Specifying UNROLL=1 effectively disables loop
                  unrolling.

                  On I64 systems, you do not have the ability to
                  control the number of times a loop is unrolled. You
                  can either disable loop unrolling with UNROLL=1,
                  or accept the UNROLL=0 default, which lets the
                  optimizer determine the unroll amount.

    The default is /OPTIMIZE, which is equivalent to
    /OPTIMIZE=LEVEL=4.

 2.37 - /PENDING_INSTANTIATIONS

       /PENDING_INSTANTIATIONS
       /PENDING_INSTANTIATIONS[=n]
       /PENDING_INSTANTIATIONS=64(D)

    Limit the depth of recursive instantiations so that infinite
    instantiation loops can be detected before some resource is
    exhausted. The /PENDING_INSTANTIATIONS qualifier requires a
    positive non-zero value as argument and issues an error when
    n instantiations are pending for the same class template. The
    default value for n is 64.

 2.38 - /POINTER_SIZE

       /POINTER_SIZE
       /POINTER_SIZE=option
       /NOPOINTER_SIZE (D)

    Controls whether pointer-size features are enabled, and whether
    pointers are 32 bits or 64 bits long.

    On both Alpha and I64 systems, the default is /NOPOINTER_SIZE,
    which disables pointer-size features, such as the ability to use
    #pragma pointer_size, and directs the compiler to assume that all
    pointers are 32-bit pointers. This default represents no change
    over previous versions of HP C++.

    You can specify one of the following options:

    SHORT        The compiler assumes 32-bit pointers.
    32           Same as SHORT.
    LONG         The compiler assumes 64-bit pointers.
    LONG[=ARGV]  The compiler assumes 64-bit pointers. If the ARGV
                 option to LONG or 64 is present, the main argument
                 argv will be an array of long pointers instead of an
                 array of short pointers. (I64 only)
    64           Same as LONG.

    Specifying /POINTER_SIZE=32 directs the compiler to assume that
    all pointers are 32-bit pointers. But unlike the default of
    /NOPOINTER_SIZE, /POINTER_SIZE=32 enables use of the #pragma
    pointer_size long and #pragma pointer_size short preprocessor
    directives to control pointer size throughout your program.

    Specifying /POINTER_SIZE=64 directs the compiler to assume that
    all pointers are 64-bit pointers, and also enables use of the
    #pragma pointer_size directives.

 2.39 - /PREFIX_LIBRARY_ENTRIES

       /PREFIX_LIBRARY_ENTRIES
       /PREFIX_LIBRARY_ENTRIES=(option,...)
       /NOPREFIX_LIBRARY_ENTRIES
       /PREFIX_LIBRARY_ENTRIES=ALL_ENTRIES (D)

    Controls C Run-Time Library (RTL) name prefixing. For user
    programs that do not include the ANSI header files but call the
    ANSI library, the compiler automatically adds a DECC$ prefix to
    all C RTL library calls just before the name for the external
    reference or global definition is put into the object file. The
    C RTL shareable image (DECC$SHR.EXE) resides in IMAGELIB.OLB
    with a DECC$ prefix for its entry points. Every external name in
    IMAGELIB.OLB has a DECC$ prefix, and, therefore, has an OpenVMS-
    conformant name space (a requirement for inclusion in IMAGELIB).

    The options are as follows:

    Option           Usage

    EXCEPT=(name,...)The names specified are not prefixed.
    ALL_ENTRIES      All HP C++ names are prefixed.

                     Note: ALL_ENTRIES prefixes all functions defined
                     by the C99 standard, including those that
                     may not be supported in the current run-time
                     library. So calling functions introduced in
                     C99 that are not yet implemented in the OpenVMS
                     C RTL will produce unresolved references to
                     symbols prefixed by DECC$ when the program is
                     linked. In addition, the compiler will issue a
                     CC-W-NOTINCRTL message when it prefixes a name
                     that is not in the current C RTL.
    ANSI_C89_        Only ANSI/ISO C library names are prefixed.
    ENTRIES
    RTL=name         References to the C RTL, indicated by NAME,
                     are generated. NAME must be 1017 characters or
                     fewer.

    If you want no names prefixed, specify /NOPREFIX_LIBRARY_ENTRIES.

 2.40 - /PREPROCESS_ONLY

       /PREPROCESS_ONLY
       /PREPROCESS_ONLY[=filename]
       /NOPREPROCESS_ONLY (D)

    Causes the compiler to perform only the actions of the
    preprocessor phase and write the resulting processed text out
    to a file. The default output file extension is .IXX. Use of
    /PREPROCESS_ONLY prevents the generation of an object or XREF
    file.

 2.41 - /PSECT_MODEL

       /PSECT_MODEL
       /PSECT_MODEL=MULTILANGUAGE
       /PSECT_MODEL=NOMULTILANGUAGE (D)

    Controls whether the compiler allocates the size of overlaid
    psects to ensure compatibility when the psect is shared by code
    created by other HP compilers.

    This qualifier solves a problem that can occur when a psect
    generated by a Fortran COMMON block is overlaid with a psect
    consisting of a C struct. Because Fortran COMMON blocks are not
    padded, if the C struct is padded, the inconsistent psect sizes
    can cause linker error messages.

    Compiling with /PSECT_MODEL=MULTILANGUAGE ensures that
    the compiler uses a consistent psect size allocation
    scheme. The corresponding Fortran squalifier is
    /ALIGN=COMMON=[NO]MULTILANGUAGE.

    The default is /PSECT=NOMULTILANGUAGE, which should be sufficient
    for most applications.

 2.42 - /PURE_CNAME

       /PURE_CNAME
       /PURE_CNAME (D) (/STANDARD=STRICT_ANSI)
    /NOPURE_CNAME (D) (All other modes)

    Affects insertion of the names into the global namespace by
    <cname> headers.

    In /PURE_CNAME mode, the <cname> headers insert the names into
    the std namespace only, as defined by the C++ Standard. In this
    mode, the __PURE_CNAME and __HIDE_FORBIDDEN_NAMES  macros are
    predefined by the compiler.

    In /NOPURE_CNAME mode, the <cname> headers insert the name into
    the std namespace and also into the global namespace. In this
    mode, the __PURE_CNAME and __HIDE_FORBIDDEN_NAMES  macros are not
    predefined by the compiler.

    The default depends on the standard mode:

    o  In /STANDARD=STRICT_ANSI mode, the default is /PURE_CNAME.

    o  In all other standard modes, the default is /NOPURE_CNAME.

    Inclusion of a <name> header instead of its <cname> counterpart
    (for example, <stdio.h> instead of <cstdio>) results in inserting
    names defined in the header into both the std namespace and the
    global namespace. Effectively, this is the same as the inclusion
    of a <cname> header in /NOPURE_CNAME mode.

 2.43 - /QUIET

       /QUIET
       /QUIET
       /NOQUIET (D)

    Specifying /QUIET causes the compiler to report errors like
    the Version 5.n compiler (issue fewer messages). This is the
    default for ARM mode (/STANDARD=ARM). All other modes default to
    /NOQUIET.

    Use /WARNINGS=ENABLE to enable specific messages normally
    disabled with /QUIET.

 2.44 - /REENTRANCY

       /REENTRANCY
       /REENTRANCY=option
       /REENTRANCY=TOLERANT (D)

    Controls the type of reentrancy that reentrant HP C RTL routines
    exhibit. (See also the DECC$SET_REENTRANCY RTL routine.)

    This qualifier is for use only with a module containing the main
    routine.

    The reentrancy level is set at run time according to the
    /REENTRANCY qualifier specified while compiling the module
    containing the main routine. This option affects the behavior
    of the C RTL, but has no effect on the C++ libraries.

    You can specify one of the following options:

    Option     Usage

    AST        Uses the __TESTBITSSI built-in function to perform
               simple locking around critical sections of RTL code,
               and may additionally disable asynchronous system traps
               (ASTs) in locked region of codes. This type of locking
               should be used when AST code contains calls to DEC C
               RTL I/O routines.
    MULTITHREADDesigned to be used in conjunction with the DECthreads
               product. It performs DECthreads locking and never
               disables ASTs.
    NONE       Gives optimal performance in the RTL, but does
               absolutely no locking around critical sections of
               RTL code. It should be used only in a single threaded
               environment when there is no chance that the thread of
               execution will be interrupted by an AST that would call
               the HP C RTL.
    TOLERANT   Uses the __TESTBITSSI built-in function to perform
               simple locking around critical sections of RTL code,
               but ASTs are not disabled. This type of locking should
               be used when ASTs are used and must be delivered
               immediately. This is the default reentrancy type.

 2.45 - /REPOSITORY

       /REPOSITORY
       /REPOSITORY=(PATHNAME [,...])
       /REPOSITORY=[.CXX_REPOSITORY] (D)

    Specifies a repository that C++ uses to store requested template
    instantiations. The default is /REPOSITORY=[.CXX_REPOSITORY]. If
    multiple repositories are specified, only the first is considered
    writable and the default repository is ignored unless specified.

 2.46 - /ROUNDING_MODE

       /ROUNDING_MODE
       /ROUNDING_MODE=option
       /ROUNDING_MODE=NEAREST (D)

    Lets you select an IEEE rounding mode if /FLOAT=IEEE_FLOAT is
    specified. The options are as follows:

    Option     Usage

    CHOPPED    Rounds toward 0.
    DYNAMIC    Sets the rounding mode for IEEE floating-point
               instructions dynamically, as determined from the
               contents of the floating-point control register.
    MINUS_     Rounds toward minus infinity.
    INFINITY
    NEAREST    Sets the normal rounding mode (unbiased round to
               nearest). This is the default.

    If you specify either /FLOAT=G_FLOAT or /FLOAT=D_FLOAT, then
    rounding defaults to /ROUNDING_MODE=NEAREST, with no other choice
    of rounding mode.

 2.47 - /RTTI

       /RTTI
       /RTTI (D)
       /NORTTI (Alpha only)

    Enables or disables support for RTTI (runtime type
    identification) features: dynamic_cast and typeid. Disabling
    runtime type identification can also save space in your object
    file because static information to describe polymorphic C++
    types is not generated. The default is to enable runtime type
    information features and generate static information in the
    object file. The /RTTI qualifier defines the macro __RTTI.

    Note that specifying /NORTTI does not disable exception handling.

 2.48 - /SHARE_GLOBALS

       /SHARE_GLOBALS
       /SHARE_GLOBALS
       /NOSHARE_GLOBALS (D)

    Controls whether the initial extern_model is shared or not
    shared (for those extern_models where it is allowed). The initial
    extern_model of the compiler is a fictitious pragma constructed
    from the settings of the /EXTERN_MODEL and /SHARE_GLOBALS.

    The default value is /NOSHARE_GLOBALS, which has the following
    effects:

    o  When linking old object files or object libraries with newly
       produced object files, you might get "conflicting attributes
       for psect" messages, which can be safely ignored as long as
       you are not building shareable libraries.

    o  The /noshare_globals default makes building shareable
       libraries easier.

 2.49 - /SHOW

       /SHOW
       /SHOW=(option[,...])
       /SHOW=(HEADER,SOURCE) (D)

    Used with the /LIST qualifier to set or cancel specific listing
    options. You can select the following options:

    Option       Usage

    ALL          Print all listing information.
    [NO]HEADER   Print/do not print header lines at the top of each
                 page (D = HEADER)
    [NO]INCLUDE  Print/do not print contents of #include files (D =
                 NOINCLUDE)
    NONE         Print no listing information
    [NO]SOURCE   Print/do not print source file statements (D =
                 SOURCE)
    [NO]STATISTICPrint/do not print compiler performance
                 statistics (D = NOSTATISTICS). On I64 systems, the
                 /SHOW=STATISTICS option is ignored.

 2.50 - /STANDARD

       /STANDARD
       /STANDARD=(option)
       /STANDARD=RELAXED (D)

    The compiler implements the International ANSI C++ Standard. The
    /STANDARD qualifier directs the compiler to interpret source code
    according to certain nonstandard syntax conventions followed by
    other implementations of the C++ language. The options are:

    Option    Usage

    RELAXED   Allow language constructs required by the International
              ANSI C++ Standard. This mode also supports some
              non-ANSI extensions and issues messages for some
              nonstandard usage that does not strictly comply with
              the standard. This is the default compiler mode. This
              option also defines the macro __STD_ANSI. Please note
              that ANSI is accepted as a synonym for RELAXED to be
              compatible with previous C++ versions.
    ARM       Minimize source changes when compiling programs
              developed using Version 5.n. This option also defines
              the macro __STD_ARM. The /STANDARD=ARM qualifier uses
              the pre-ansi AT&T version of the iostream library and
              defines the macro __NO_USE_STD_IOSTREAM.
    CFRONT    As of HP C++ Version 7.1, support for /STANDARD=CFRONT
              is retired.
    GNU       Use this option if you want to compile programs
              developed using the GNU C++ compiler. This option
              also defines the __STD_GNU macro. The /STANDARD=GNU
              qualifier uses the pre-ansi AT&T version of the
              iostream library and defines the macro __NO_USE_
              STD_IOSTREAM. The following changes in behavior are
              provided for compatibility with the GNU C++ compiler:

              o  These options are enabled by default:

                    /ALTERNATIVE_TOKENS
                    /TEMPLATE_DEFINE=LOCAL
                    /NOIMPLICIT_INCLUDE

              o  Access control is not enforced for types defined
                 inside a class.

              o  Unrecognized character escape sequences in string
                 literals produce an informational instead of a
                 warning message.

              o  The __INLINE keyword is enabled and is equivalent to
                 inline.

              o  The severity of the error "incompatible parameter"
                 (tag incompatibleprm) is reduced to warning.

              o  When overloading, enum types are treated as integral
                 types.

              The following known incompatibility is not addressed in
              the /STANDARD=GNU mode:

              o  The compiler strictly enforces the requirement
                 to define functions before they are used. This
                 requirement also applies to built-in functions such
                 as strlen.

    MS        Allow language constructs supported by the Visual C++
              compiler. This option also defines the macro __STD_
              MS. The /STANDARD=MS qualifier uses the pre-ansi AT&T
              version of the iostream library and defines the macro
              __NO_USE_STD_IOSTREAM.
    STRICT_   Enforce the ANSI standard strictly but permit some ANSI
    ANSI      violations that should be errors to be warnings. This
              option also defines the macro __STD_STRICT_ANSI. To
              force ANSI violations to be issued as errors instead
              of warnings, use /WARNINGS=ANSI_ERRORS in addition to
              /STANDARD=STRICT_ANSI. This combination defines the
              macro __STD_STRICT_ANSI_ERRORS. The /STANDARD=STRICT_
              ANSI qualifier uses the ANSI/ISO standard version of
              the iostream library and defines the macro __USE_STD_
              IOSTREAM.
    LATEST    Latest C++ standard dialect (Alpha, I64).
              /STANDARD=LATEST is currently equivalent to
              /STANDARD=STRICT_ANSI, but is subject to change when
              newer versions of the C++ standard are released.

    For more information on the effect of the /STANDARD qualifier on
    HP C++ compile-time error checking, "Compiler Compatibility" in
    the HP C++ User's Guide for OpenVMS Systems.

 2.51 - /TEMPLATE_DEFINE

       /TEMPLATE_DEFINE=(option,...)
       /NOTEMPLATE_DEFINE

    Controls compiler behavior pertaining to the instantiation of C++
    templates. See "Using Templates" in the HP C++ User's Guide for
    OpenVMS Systems for details on how to instantiate templates using
    this qualifier.

    Note that you must specify a value for /TEMPLATE_DEFINE.

    Select only one of the following optional values to determine the
    template instantiation model:

    Option                Usage

    ALL                   Instantiate all template entities declared
                          or referenced in the compilation unit,
                          including typedefs. For each fully
                          instantiated template class, all its
                          member functions and static data members
                          are instantiated even if they were not
                          used. Nonmember template functions are
                          instantiated even if the only reference
                          was a declaration. Instantiations are
                          created with external linkage. Overrides
                          /REPOSITORY at compile time. Instantiations
                          are placed in the user's object file
    ALL_REPOSITORY        Instantiate all templates declared or
                          used in the source program and put the
                          object code generated as separate object
                          files in the repository. Instantiations
                          caused by manual instantiation directives
                          are also put in the repository. This is
                          similar to /TEMPLATE_DEFINE=ALL except that
                          explicit instantiations are also put in the
                          repository, rather than than an external
                          symbol being put in the main object file.
                          This qualifier is useful for creating a
                          pre-instantiation library.
    AUTOMATIC             Directs the compiler to use the automatic
                          instantiation model of C++ templates.
                          /TEMPLATE_DEFINE=AUTOMATIC is the default.
    NOAUTOMATIC           Directs the compiler to not implicitly
                          instantiate templates.
    IMPLICIT_LOCAL        Same as /TEMPLATE_DEFINE=LOCAL, except
                          manually instantiated templates are placed
                          in the repository with external linkage.
                          This is useful for build systems that need
                          to have explicit control of the template
                          instantiation mechanism. This mode can
                          suffer the same limitations as /TEMPLATE_
                          DEFINE=LOCAL. This mode is the default when
                          /STANDARD=GNU is specified.
    LOCAL                 Similar to /TEMPLATE_DEFINE=USED except
                          that the functions are given internal
                          linkage. This qualifier provides a
                          simple mechanism for getting started with
                          templates. The compiler instantiates as
                          local functions the functions used in
                          each compilation unit, and the program
                          links and runs correctly (barring problems
                          resulting from multiple copies of local
                          static variables). However, because many
                          copies of the instantiated functions can be
                          generated, this qualifier might not be not
                          suitable for production use.

                          The /TEMPLATE_DEFINE=LOCAL qualifier cannot
                          be used in conjunction with automatic
                          template instantiation. If automatic
                          instantiation is enabled by default, it
                          is disabled by the /TEMPLATE_DEFINE=LOCAL
                          qualifier. Explicit use of /TEMPLATE_
                          DEFINE=LOCAL and /TEMPLATE_DEFINE=AUTO
                          is an error.
    USED                  Instantiate those template entities that
                          were used in the compilation. This includes
                          all static data members for which there are
                          template definitions. Overrides /TEMPLATE_
                          DEFINE=AUTO at compile time.
    USED_REPOSITORY       Like ALL_REPOSITORY, but instantiates only
                          templates used by the compilation. The
                          explicit instantiations are also put into
                          the repository as separate object files.

    The following /TEMPLATE_DEFINE optional values are independent of
    the model used and each other:

    Option                Usage

    DEFINITION_FILE_      Specifies a string that contains a
    TYPE="file-type-      list of file types that are valid for
    list"                 template definition files. Items in
                          the list must be separated by commas
                          and preceded by a period. A type is not
                          allowed to exceed the OpenVMS limit of 31
                          characters. This qualifier is applicable
                          only when automatic instantiation has
                          been specified. The default is /TEMPLATE_
                          DEFINE=DEF=".CXX,.C,.CC,.CPP".
    PRAGMA                Determines whether the compiler ignores
                          #pragma define_template directives
                          encountered during the compilation. This
                          qualifier lets you quickly switch to
                          automatic instantiation without having
                          to remove all the pragma directives from
                          your program's code base. The default is
                          /TEMPLATE_DEFINE=PRAGMA, which enables
                          #pragma define_template.
    VERBOSE               Turns on verbose or verify mode to display
                          each phase of instantiation as it occurs.
                          During the compilation phase, informational
                          level diagnostics are generated to indicate
                          which templates are automatically being
                          instantiated. This qualifier is useful as a
                          debugging aid.
    TIMESTAMP (Alpha      only applicable if a repository is being
    only)                 used. Causes the compiler to create a
                          timestamp file named TIMESTAMP. in the
                          repository. Thereafter, instantiations are
                          added or regenerated only if needed; that
                          is, if they do not alreay exist, or if
                          existing ones are older than the timestamp.
                          Also see /REPOSITORY.

    Also see /PENDING_INSTANTIATIONS.

 2.52 - /UNDEFINE

       /UNDEFINE
       /UNDEFINE=(identifier[,...])
       /NOUNDEFINE (D)

    Performs the same function as the #undefine preprocessor
    directive: it cancels a macro definition.

    The /UNDEFINE qualifier is useful for undefining the predefined
    C++ preprocessor constants. For example, if you use a
    preprocessor constant to conditionally compile segments of code
    specific to C++ for OpenVMS systems, you can undefine constants
    to see how the portable sections of your program execute. For
    example:

     /UNDEFINE="deccxx"

    When both /DEFINE and /UNDEFINE are present on the CXX command
    line, /DEFINE is evaluated before /UNDEFINE.

 2.53 - /UNSIGNED_CHAR

       /UNSIGNED_CHAR
       /UNSIGNED_CHAR
       /NOUNSIGNED_CHAR (D)

    The /UNSIGNED_CHAR qualifier changes the default for all
    char types from signed to unsigned. The /NOUNSIGNED_CHAR
    qualifier causes all plain char declarations to have the same
    representation and set of values as signed char declarations.

 2.54 - /USING_STD

       /USING_STD
       /USING_STD
       /NOUSING_STD (D)

    Controls whether standard library header files are processed as
    though the compiled code were written as follows:

    using namespace std;
    #include <header>

    These options are provided for compatibility for users who do not
    want to qualify use of each standard library name with std:: or
    put using namespace std; at the top of their sources.

    /USING_STD turns implicit using namespace std on; this is
    the default when compiling /STANDARD=ARM, /STANDARD=GNU,
    /STANDARD=MS, or /STANDARD=RELAXED.

    /NOUSING_STD turns implicit using namespace std off; this is the
    default when compiling /STANDARD=STRICT_ANSI.

 2.55 - /VERSION

       /VERSION
       /VERSION
       /NOVERSION (D)

    Causes the compiler to identify (print out) its version and
    operating system. The listing file also contains the compiler
    version. You cannot specify this qualifier with any other
    qualifiers.

 2.56 - /WARNINGS

       /WARNINGS
       /WARNINGS[=(option[,...])]
       /WARNINGS (D)
       /NOWARNINGS

    Controls the issuance of compiler diagnostic messages and lets
    you modify the severity of messages.

    The default qualifier, /WARNINGS, outputs all enabled warning
    and informational messages for the compiler mode you are using.
    The /NOWARNINGS qualifier suppresses warning and informational
    messages.

    Options apply only to warning and informational messages.

    The message-list in the following table of options can be any one
    of the following:

    o  A single message identifier (within parentheses, or not). The
       message identifier is the name following the message severity
       letter on the first line of an issued message. For example, in
       the following message, the message identifier is GLOBALEXT:

       %CC-W-GLOBALEXT, a storage class of globaldef, globalref, or globalvalue
       is a language extension.

    o  A comma-separated list of message identifiers, enclosed in
       parentheses.

    o  The keyword ALL.

    The options are processed and take effect in the following order:

    NOWARNINGS             Suppresses warnings.
    NOINFORMATIONALS       Suppresses informational messages.
    ENABLE=message-list    Enables issuance of the specified
                           messages. Can be used to enable specific
                           messages that normally would not be issued
                           when using /QUIET or messages disabled
                           with /WARNINGS=DISABLE.
    DISABLE=message-list   Disables issuance of the specified
                           messages. Can be used for any nonerror
                           message specified by a message number
                           or tag. Specify ALL to suppress all
                           informationals and warnings.
    INFORMATIONALS=message-Sets the severity of all specified
    list                   messages to Informational. Fatal and Error
                           messages cannot be made less severe. Can
                           also be used to enable informationals that
                           are disabled by default.

                           Note: With C++ Version 7.1, using
                           /WARNINGS=INFORMATIONALS=<tag> no longer
                           enables all other informational messages.
    WARNINGS=message-      Sets the severity of the specified
    list                   messages to Warning. Fatal and Error
                           messages cannot be made less severe.
    [NO]ANSI_ERRORS        Issues error messages for all ANSI
                           violations when in STRICT_ANSI mode. The
                           default is /WARNINGS=NOANSI_ERRORS.
    [NO]TAGS               Displays a descriptive tag at the end
                           of each message. "D" indicates that the
                           severity of the message can be controlled
                           from the command line. The tag displayed
                           can be used as the message identifier in
                           the /WARNINGS qualifier options.
    ERRORS=message-list    Sets the severity of the specified
                           messages to Error.

                           Supplied Error and Fatal messages cannot
                           be made less severe. (Exception: A message
                           can be upgraded from Error to Fatal, then
                           later downgraded to Error again, but it
                           can never be downgraded from Error.)

                           Warnings and Informationals can be made
                           any severity.
    FATALS=message-list    Sets the severity of the specified
                           messages to Fatal.

    Also see the #pragma message preprocessor directive.

 2.57 - /XREF

       /XREF (Alpha only)
       /XREF[=file-spec]
       /NOXREF (D)

    Controls whether the compiler generates a file of source code
    analysis information. The default file name is the file name of
    the primary source file; the default file type is .XREF. Use the
    SCA IMPORT command to convert an .XREF file into an analysis data
    file that is ready for loading into an SCA library.

  3 - Language Topics

    This section discusses language topics.

 3.1 - Built-In Functions

    Built-in functions allow you direct access hardware and machine
    instructions to perform operations that are cumbersome, slow, or
    impossible in pure C.

    These functions are efficient because they are built into the C++
    compiler. This means that a call to one of these functions does
    not result in a reference to a function in the C run-time library
    or in your programs. Instead, the compiler generates the machine
    instructions necessary to carry out the function directly at
    the call site. Because most of these built-in functions closely
    correspond to single Alpha or I64 machine instructions, the
    result is small, fast code.

    Some of these functions (such as those that operate on strings or
    bits) are of general interest. Others (such as the functions
    dealing with process context) are of interest if you are
    writing device drivers or other privileged software. Some of the
    functions are privileged and unavailable to user mode programs.

    Be sure to include the <builtins.h> header file in your source
    program to access these built-in functions.

    C++ supports the #pragma builtins preprocessor directive for
    compatibility with VAX C, but it is not required.

    Some of the built-in functions have optional arguments or allow
    a particular argument to have one of many different types.
    To describe different valid combinations of arguments, the
    description of each built-in function may list several different
    prototypes for the function. As long as a call to a built-in
    function matches one of the prototypes listed, the call is valid.
    Furthermore, any valid call to a built-in function acts as if the
    corresponding prototype was in scope, so the compiler performs
    the argument checking and argument conversions specified by that
    prototype.

    The majority of the built-in functions are named after the
    machine instruction that they generate. For more information
    on these built-in functions, see the documentation on the
    corresponding machine instruction. In particular, see that
    reference for the structure of queue entries manipulated by the
    queue built-in functions.

    The C++ built-in functions available on OpenVMS Alpha systems
    are also available on I64 systems, with some differences. There
    are also built-in functions specific to I64 systems. For more
    information on built-in functions, see "Built-In Functions" in
    the HP C++ User's Guide for OpenVMS Systems.

    Translation_Macros

    C++ for OpenVMS Alpha and I64 systems does not support the VAX
    C built-in functions. However, the <builtins.h> header file
    contains macro definitions that translate some VAX C builtins
    to the equivalent C++ for OpenVMS Alpha builtins. Consequently,
    the following VAX C builtins are effectively supported:

       _BBCCI (position, address)
       _BBSSI (position, address)
       _INSQHI (new_entry, head)
       _INSQTI (new_entry, head)
       _INSQUE (new_entry, predecessor)
       _REMQHI (head, removed_entry)
       _REMQTI (head, removed_entry)
       _PROBER (mode, length, address)
       _PROBEW (mode, length, address)

    Intrinsic Functions

    On OpenVMS Alpha systems, C++ supports in-line assembly code,
    commonly called ASMs on UNIX platforms.

    OpenVMS I64 systems do not support ASMs.

    Like builtin-functions, ASMs are implemented with a function-
    call syntax. But unlike built-in functions, to use ASMs you
    must include the <c_asm.h> header file containing prototypes for
    the three types of ASMs, and the #pragma intrinsic preprocessor
    directive.

    Syntax:

    __int64 asm(const char *, ...);  /* for integer operations,
                                        like mulq */

    float fasm(const char *, ...);   /* for single precision float
                                        instructions */

    double dasm(const char *, ...);  /* for double precision float
                                        instructions */

             #pragma intrinsic (asm)
             #pragma intrinsic (fasm)
             #pragma intrinsic (dasm)

    The first argument to the asm, fasm, or dasm function contains
    the instruction(s) to be generated inline and the metalanguage
    that describes the interpretation of the arguments.

    The remaining arguments (if any) are the source and destination
    arguments for the instruction being generated.

 3.2 - Variable Length Argument Lists

    The set of functions and macros defined and declared in the
    <varargs.h> and the <stdarg.h> header files provide a method
    of accessing variable-length argument lists. (Note that the
    <stdarg.h> functions are defined by the ANSI C++ standard and
    are, therefore, portable as compared with those defined in
    <varargs.h>.)

    The C++ RTL functions such as printf and execl, for example,
    use variable-length argument lists. User-defined functions with
    variable-length argument lists that do not use <varargs.h> or
    <stdarg.h> are not portable due to the different argument-passing
    conventions of various machines.

    To use these functions and macros in <stdarg.h>, you must include
    the <stdarg.h> header file with the following preprocessor
    directive:

          #include <stdarg.h>

    The <stdarg.h> header file declares a type (va_list) and three
    macros (va_start, va_arg, and va_end) for advancing through a
    list of function arguments of varying number and type. The macros
    have the following syntax:

          void va_start(va_list ap, parmN);

          type va_arg(va_list ap, type);

          void va_end(va_list ap);

    The va_start macro initializes the object ap of type va_list
    for subsequent use by va_arg and va_end. The va_start macro
    must be invoked before any access to the unnamed arguments. The
    parameter parmN is the identifier of the rightmost parameter in
    the variable parameter list of the function definition. If parmN
    is declared with the register storage class, with a function
    or array type, or with a type that is not compatible with the
    type that results after application of the default arguments
    promotions, the behavior is undefined. The va_start macro returns
    no value.

    The va_arg macro expands to an expresion that has the type and
    value of the next argument in the call. The parameter ap is the
    same as the one initialized by va_start. Each invocation of va_
    arg modifies ap so that the values of successive arguments are
    returned in turn. The parameter "type" is a type name specified
    such that the type of a pointer to an object that has the
    specified type can be obtained by postfixing an asterisk (*)
    to "type". If there is no actual next argument, or if type is not
    compatible with the type of the next actual argument (as promoted
    according to the default argument promotions), the behavior
    is undefined. The first invocation of va_arg after that of va_
    start returns the value of the argument after that specified by
    parmN. Successive invocations return the values of the remaining
    arguments in turn.

    The va_end macro facilitates a normal return from the function
    whose variable argument list was referred to by the expansion
    of va_start that initialized the va_list ap object. The va_end
    macro can modify ap) so that it can no longer be used (without an
    intervening invocation of va_start). If there is no corresponding
    invocation of va_start or if va_end is not invoked before the
    return, the behavior is undefined. The va_end macro returns no
    value.

 3.3 - Preprocessor

    The C++ preprocessor uses directives to affect the compilation of
    a source file. For C++ on OpenVMS systems, these directives are
    processed by an early phase of the compiler, not by a separate
    program.

    The preprocessor directives begin with a number sign (#) and
    do not end with a semicolon. The number sign must appear in the
    first column of the source line.

    o  Null_directive (#)

       A preprocessing directive of the form # <newline> is a null
       directive and has no effect.

    o  Conditional_Compilation

       Conditional compilation is provided by the following
       directives:

          #if constant-expression - Checks whether the constant
          expression is nonzero (true).
          #ifdef identifier - Checks whether the identifier is
          defined.
          #ifndef identifier - Checks whether the identifier is
          undefined.
          #else - Introduces source lines to be compiled as an
          alternative to the conditions tested by the previous
          directives.
          #elif constant-expression - Delimits alternative source
          lines to be compiled if the constant expression in the
          corresponding #if, ##ifdef, or #ifndef directive is false
          and if the additional constant expression presented in the
          #elif directive is true. An #elif directive is optional.
          #endif - Ends the scope of the previous directives.

       If the condition checked by #if, #ifdef, or #ifndef is true,
       then all lines between the #else, #elif, and #endif are
       ignored. If the condition is false, then any lines between
       the conditional directive and the #else or #elif (if any)
       are ignored. If there is no #else, then the lines between the
       conditional and the #endif are ignored.

    o  #define

       The #define preprocessor directive has the form:

             #define identifier token-string

       The preprocessor substitutes the token string everywhere
       in the program that it finds the identifier except within
       comments, character constants, or string constants.

       Macro replacements are defined in a #define directive of the
       following form:

             #define name([parm1[,parm2,...]]) token-string

       Within the program, all macro references that have the
       following form are replaced by the token string. The arguments
       in the macro reference replace the corresponding parameters in
       the token string.

             name([arg1[,arg2,...]])

    o  #error

       The #error directive issues an optional diagnostic message,
       and ends compilation. This directive has the following form:

             #error [message]

    o  #include

       The #include directive instructs the preprocessor to insert
       the contents of the specified file or module into the program.
       An #include directive can have one of three forms:

             #include "filespec"
             #include <filespec>
             #include module-name

       The first two forms are ANSI-compliant methods of file
       inclusion and are therefore more portable. In these forms,
       .h is the default file type, unless the compiler is instructed
       to supply no default type (that is, a type of just ".") by the
       /ASSUME=NOHEADER_TYPE_DEFAULT qualifier.

       The third form is specific to OpenVMS systems for specifying
       the inclusion of a module from a text library, and is not
       generally needed or recommended because the ANSI forms also
       cause the text libraries to be searched.

       For the order of search, see /INCLUDE_DIRECTORY.

       There is no defined limit to the nesting level of #include
       files and modules.

    o  #line

       The #line directive applies a specified line number and
       optional file specification to the next line of source
       text. This can be useful for diagnostic messages. The #line
       directive has the following forms:

             #line integer-constant
             #line integer-constant "filename"
             #line pp-tokens

       In the first two forms, the compiler gives the line following
       a #line directive the number specified by the integer
       constant. The optional filename in quotation marks indicates
       the name of the source file that the compiler will provide in
       its diagnostic messages. If the filename is omitted, the file
       name used is the name of the current source file or the last
       filename specified in a previous #line directive.

       In the third form, macros in the #line directive are expanded
       before it is interpreted. This allows a macro call to expand
       into the integer-constant, filename, or both. The resulting
       #line directive must match one of the other two forms, and is
       then processed as appropriate.

    o  #pragma

       The #pragma directive performs compiler-specific tasks as
       designated by each implementation of the C language. HP C++
       for OpenVMS Systems supports the following pragmas:

 #pragma [no]builtins

       Enables the C++ built-in functions that directly access
       processor instructions. If the pragma does not appear in your
       program, the default is #pragma nobuiltins.

       C++ supports the #pragma builtins preprocessor directive for
       compatibility with VAX C, but it is not required.

 #pragma define_template

       Instructs the compiler to instantiate a template with the
       arguments specified in the pragma.

       Syntax:

       #pragma define_template identifier

       For example, the following statement instructs the compiler to
       instantiate the template mytempl with the arguments arg1 and
       arg2:

       #pragma define_template mytempl<arg1, arg2>

 #pragma environment

       Sets, saves, or restores the states of context pragmas.
       This directive protects include files from contexts set by
       encompassing programs, and protects encompassing programs from
       contexts that could be set in header files that they include.

       The #pragma environment directive affects the following
       pragmas:

       o  #pragma extern_model

       o  #pragma extern_prefix

       o  #pragma member_alignment

       o  #pragma message

       o  #pragma pointer_size

       o  #pragma required_pointer_size

       Syntax:

                 #pragma environment command_line
                 #pragma environment header_defaults
                 #pragma environment restore
                 #pragma environment save

       command_line      Sets, as specified on the command line, the
                         states of all the context pragmas. You can
                         use this pragma to protect header files from
                         environment pragmas that take effect before
                         the header file is included.
       header_defaults   Sets the states of all the context pragmas
                         to their default values. This is almost
                         equivalent to the situation in which a
                         program with no command-line options and
                         no pragmas is compiled, except that this
                         pragma sets the #pragma message state to
                         #pragma nostandard, as is appropriate for
                         header files.
       save              Saves the current state of every pragma that
                         has an associated context.
       restore           Restores the current state of every pragma
                         that has an associated context.

 #pragma extern_model

       Controls the compiler's interpretation of objects that have
       external linkage. This pragma lets you choose the global
       symbol model to be used for externs.

       Syntax:

       #pragma extern_model common_block [attr[,attr]...]
       #pragma extern_model relaxed_refdef [attr[,attr]...]
       #pragma extern_model strict_refdef "name" [attr[,attr]...]
       #pragma extern_model strict_refdef
       #pragma extern_model globalvalue
       #pragma extern_model save
       #pragma extern_model restore

       The default model on C++ is #pragma relaxed_refdef noshr. This
       is different from the model used by VAX C, which is common
       block, shr.

       Use of an extern_model value other than relaxed_refdef should
       be limited to compilations that either declare only POD (Plain
       Old Data) objects, or that carefully use the extern_model
       #pragma (and/or environment #pragma) directives to ensure that
       declarations of non-POD objects appear only in source that is
       subject to the default extern_model of relaxed_refdef.

       The [attr[,attr]...] are optional psect attribute
       specifications chosen from the following (at most one from
       each line):

       o  gbl lcl (Not allowed with relaxed_refdef)

       o  shr noshr

       o  wrt nowrt

       o  pic nopic (Not meaningful for Alpha)

       o  ovr con

       o  rel abs

       o  exe noexe

       o  vec novec

       o  0 byte 1 word 2 long 3 quad

       o  octa 16 page

       See the HP C++ User's Guide for OpenVMS Systems for more
       information on the #pragma extern_model directive.

 #pragma extern_prefix

       Controls the compiler's synthesis of external names, which the
       linker uses to resolve external name requests.

       When you specify #pragma extern_prefix with a string
       argument, the compiler prepends the string to all external
       names produced by the declarations that follow the pragma
       specification.

       This pragma is useful for creating libraries where the
       facility code can be attached to the external names in the
       library.

       Syntax:

                 #pragma extern_prefix "string"
                 #pragma extern_prefix  save
                 #pragma extern_prefix  restore

       Where "string" prepends the quoted string to external names in
       the declarations that follow the pragma specification.

       The save and restore keywords can be used to save the current
       pragma prefix string and to restore the previously saved
       pragma prefix string, respectively.

       The default external prefix, when none has been specified by a
       pragma, is the null string.

 #pragma function

       Specifies that calls to the specified functions are not
       intrinsic but are, in fact, function calls. This pragma has
       the opposite effect of #pragma intrinsic.

       Syntax:

                 #pragma function (function1[, function2, ...])

 #pragma include_directory

       The effect of each #pragma include_directory is as if its
       string argument (including the quotes) were appended to the
       list of places to search that is given its initial value by
       the /INCLUDE_DIRECTORY qualifier, except that an empty string
       is not permitted in the pragma form.

       Syntax:

       #pragma include_directory  <string-literal>

       This pragma is intended to ease DCL command-line length
       limitations when porting applications from POSIX-like
       environments built with makefiles containing long lists of
       -I options that specify directories to search for headers.
       Just as long lists of macro definitions specified by the
       /DEFINE qualifier can be converted to #define directives in
       a source file, long lists of places to search specified by
       the /INCLUDE_DIRECTORY qualifier can be converted to #pragma
       include_directory directives in a source file.

       Note that the places to search, as described in the help
       text for the /INCLUDE_DIRECTORY qualifier, include the use
       of POSIX-style pathnames, for example "/usr/base". This form
       can be very useful when compiling code that contains POSIX-
       style relative pathnames in #include directives. For example,
       #include <subdir/foo.h> can be combined with a place to search
       such as "/usr/base" to form "/usr/base/subdir/foo.h", which
       will be translated to the filespec "USR:[BASE.SUBDIR]FOO.H"

       This pragma can appear only in the main source file or in the
       first file specified on the /FIRST_INCLUDE qualifier. Also, it
       must appear before any #include directives.

 #pragma [no]inline

       Expands function calls inline. The function call is replaced
       with the function code itself.

       Syntax:

                 #pragma inline (id,...)
                 #pragma noinline (id,...)

       If a function is named in an inline directive, calls to that
       function will be expanded as inline code, if possible.

       If a function is named in a noinline directive, calls to that
       function will not be expanded as inline code.

       If a function is named in both an inline and a noinline
       directive, an error message is issued.

       For calls to functions named in neither an inline nor a
       noinline directive, C++ expands the function as inline code
       whenever appropriate as determined by a platform-specific
       algorithm.

 #pragma intrinsic

       Specifies that calls to the specified functions are intrinsic
       (that is, handled internally by the compiler, allowing it to
       generate inline code, move or eliminate calls, or do various
       other optimizations). This pragma is only valid for functions
       that are known to the compiler.

       Syntax:

                 #pragma intrinsic (function1[, function2, ...])

 #pragma [no]member_alignment

       Tells the compiler to align structure members on the next
       boundary appropriate to the type of the member rather than the
       next byte. For example, a long variable is aligned on the next
       longword boundary; a short variable on the next word boundary.

       Syntax:

                 #pragma nomember_alignment [base_alignment]
                 #pragma member_alignment [save | restore]

       The optional base_alignment parameter can be used with #pragma
       nomember_alignment to specify the base alignment of the
       structure. Use one of the following keywords to specify the
       base_alignment:

       o  BYTE (1 byte)

       o  WORD (2 bytes)

       o  LONGWORD (4 bytes)

       o  QUADWORD (8 bytes)

       o  OCTAWORD (16 bytes)

       The optional save and restore keywords can be used to save
       the current state of the member_alignment and to restore
       the previous state, respectively. This feature is necessary
       for writing header files that require member_alignment or
       nomember_alignment, or that require inclusion in a member_
       alignment that is already set.

 #pragma message

       Controls the issuance of individual diagnostic messages or
       groups of messages. Use of this pragma overrides any command-
       line options that may affect the issuance of messages.

       Syntax:

                 #pragma message option1 message-list
                 #pragma message option2

       where option1 is:

       disable        Suppresses the issuance of the indicated
                      messages.

                         Only messages of severity Warning (W) or
                         Information (I) can be disabled. If the
                         message has severity of Error (E) or Fatal
                         (F), it is issued regardless of any attempt
                         to disable it.
       enable         Enables the issuance of the indicated messages.
       error          Sets the severity of each message in the
                      message-list to Error.
       fatal          Sets the severity of each message on the
                      message-list to Fatal.
       informational  Sets the severity of each message in the
                      message-list to Informational.
       warning        Sets the severity of each message in the
                      message-list to Warning.

       The message-list can be any one of the following:

       o  A single message identifier (within parentheses or not).

       o  A comma-separated list of message identifiers, enclosed in
          parentheses.

       o  The keyword ALL-All the messages in the compiler.

       option2 is:

       save-saves the current state of which messages are enabled and
       disabled.

       restore-restores the previous state of which messages are
       enabled and disabled.

 #pragma module

       Changes the system-recognized module name and version number.
       You can find the module name and version number in the
       compiler listing file and the linker load map.

       Syntax:

                 #pragma module identifier identifier
                 #pragma module identifier string

       The first parameter must be a valid C++ identifier. It
       specifies the module name to be used by the linker. The second
       parameter specifies the optional identification that appears
       on listings and in the object file. It must be either a valid
       DEC C identifier of 31 characters or less, or a character-
       string constant of 31 characters or less.

       Only one #pragma module directive can be processed per
       compilation unit, and that directive must appear before any
       C language text. The #pragma module directive can follow other
       directives, such as #define, but it must precede any function
       definitions or external data definitions.

 #pragma once

       Specifies that the header file is evaluated only once.

       Syntax:

       #pragma once

 #pragma pack

       Specifies the byte boundary for packing members of C
       structures.

       Syntax:

                 #pragma pack [n]

       The n specifies the new alignment restriction in bytes:

          1 - align to byte
          2 - align to word
          4 - align to longword
          8 - align to quadword
          16 - align to octaword

       A structure member is aligned to either the alignment
       specified by #pragma pack or the alignment determined by
       the size of the structure member, whichever is smaller. For
       example, a short variable in a structure gets byte-aligned
       if #pragma pack 1 is specified. If #pragma pack 2, 4, or 8 is
       specified, the short variable in the structure gets aligned to
       word.

       If #pragma pack is not used, or if it is specified without the
       n, packing defaults to 16 on OpenVMS Alpha and I64 systems,
       and to 1 (byte alignment) on OpenVMS VAX systems.

 #pragma pointer_size

       Controls whether pointers are 32-bit pointers or 64-bit
       pointers.

       Syntax:

                 #pragma pointer_size keyword

       Where keyword is one of the following:

          short-32-bit pointer
          long-64-bit pointer
          system_default-32-bit pointers on OpenVMS systems; 64-bit
          pointers on Tru64 UNIX systems
          save-Saves the current pointer size
          restore-Restores the current pointer size to its last saved
          state

       This directive is enabled only when the /POINTER_SIZE command-
       line qualifier is specified. Otherwise, #pragma pointer_size
       has the same effect as #pragma required_pointer_size.

 #pragma required_pointer_size

       Intended for use by developers of header files to control
       pointer size within header files.

       Syntax:

                 #pragma required_pointer_size keyword

       Where keyword is one of the following:

          short-32-bit pointer
          long-64-bit pointer
          system_default-32-bit pointers on OpenVMS systems; 64-bit
          pointers on Tru64 UNIX systems
          save-Saves the current pointer size
          restore-Restores the current pointer size to its last saved
          state

       This directive is always enabled, even if the /POINTER_
       SIZE command-line qualifier is omitted. Otherwise, #pragma
       required_pointer_size has the same effect as #pragma pointer_
       size.

 #pragma [no]standard

       Directs the compiler to define regions of source code where
       portability diagnostics are not to be issued.

       Use #pragma nostandard to suppress diagnostics about non-ANSI
       C extensions, regardless of the /STANDARD qualifier specified,
       until a #pragma standard directive is encountered.

       Use #pragma standard to reinstate the setting of the /STANDARD
       qualifier that was in effect before before the last #pragma
       nostandard was encountered.

       Every #pragma standard directive must be preceded by a
       corresponding #pragma nostandard directive.

       Note that this pragma does not change the current mode of the
       compiler or enable any extensions not already supported in
       that mode.

 #pragma use_linkage

       Associates a special linkage, defined by the #pragma linkage
       directive, with the specified functions.

       Syntax:

       #pragma use_linkage linkage-name (routine1, routine2, ...)

       The linkage-name is the name of a linkage previously defined
       by the #pragma linkage directive.

       The parenthesized list contains the names of functions you
       want to associated with the named linkage.

    o  #undef

       The #undef directive cancels a previously defined macro
       replacement. Any other macro replacements that occurred before
       the #undef directive remain.

       The #undef directive has the following syntax:

             #undef identifier

 3.4 - Predefined Macros

    The compiler defines the following macros and names. For more
    detailed information, see the HP C++ User's Guide for OpenVMS
    Systems. The * character following a name indicates that the name
    cannot be redefined or undefined.

    Macro                               Description

    _BOOL_EXISTS                        Indicates that bool is a type
                                        or keyword
    __BOOL_IS_A_RESERVED_WORD           Indicates that bool is a
                                        keyword
    __DATE__                            A string literal containing
                                        the date of the translation
                                        in the form Mmm dd yyyy, or
                                        Mmm d yyyy if the value of
                                        the date is less than 10
    __FILE__                            A string literal containing
                                        the name of the source file
                                        being compiled
    __IEEE_FLOAT                        Identifies floating-point
                                        format for compiling the
                                        program. The value is always
                                        1 for HP Tru64 UNIX.
    __LINE__                            A decimal constant containing
                                        the current line number in
                                        the C++ source file
    __PRAGMA_ENVIRONMENT                Indicates that that the
                                        pragma environment directive
                                        is supported.
    __TIME__                            A string literal containing
                                        the time of the translation
                                        in the form of hh:mm:ss
    _WCHAR_T                            Indicates that wchar_t is a
                                        keyword

    The following table lists names with a defined value of 1.

    Name               Description

    __cplusplus        Language identification name.
    __DECCXX           Language identification name.
    __VMS              System identification
    __vms              System identification

    The compiler predefines __VMS; the C compiler predefines VMS and
    __VMS. Therefore, C++ programmers who plan to reuse code should
    check for __VMS.

    The compiler supports the following predefined macro names:

    Name               Description

    __Alpha_AXP        System identification name
    __ALPHA            System identification name
    __alpha            System identification name
    __32BITS           Defined when pointers and data of type long
                       are 32 bits on Alpha platforms

    The compiler predefines __32BITS when pointers and data of type
    long are 32 bits on Alpha platforms.

    On both UNIX and OpenVMS Alpha operating systems, programmers
    should use the predefined macro __alpha for code that is intended
    to be portable from one system to the other.

    Predefined macros (with the exception of vms_version, VMS_
    VERSION, __vms_version, __VMS_VERSION,  and __INITIAL_POINTER_
    SIZE) are defined as 1 or 0, depending on the system (VAX or
    Alpha processor), the compiler defaults, and the qualifiers used.
    For example, if you compiled using G_FLOAT format, __D_FLOAT and
    __IEEE_FLOAT (Alpha processors only) are predefined to be 0, and
    __G_FLOAT is predefined as if the following were included before
    every compilation unit:

     #define  __G_FLOAT  1

    These macros can assist in writing code that executes
    conditionally. They can be used in #elif, #if, #ifdef, and
    #ifndef directives to separate portable and nonportable code in
    a C++ program. The vms_version, VMS_VERSION, __vms_version, and
    __VMS_VERSION macros are defined with the value of the OpenVMS
    version on which you are running (for example, Version 6.0).

    C++ automatically defines the following macros pertaining to the
    format of floating-point variables. You can use them to identify
    the format with which you are compiling your program.

       __D_FLOAT
       __G_FLOAT
       __IEEE_FLOAT
       _IEEE_FP
       __X_FLOAT

    The value of __X_FLOAT can be 0 or 1 depending on the floating
    point mode in effect. You can use the /FLOAT qualifier to change
    the mode.

    The following table lists predefined version string and version
    number macros.

    Name               Description

    __VMS_VERSION      Version identification
    __vms_version      Version identification
    __DECCXX_VER       Version identification
    __VMS_VER          Version identification

    For example, the defined value of __VMS_VERSION on OpenVMS
    Version 6.1 is character string V6.1.

    You can use __DECCXX_VER to test that the current compiler
    version is newer than a particular version and __VMS_VER to
    test that the current OpenVMS Version is newer than a particular
    version. Newer versions of the compiler and the Openvms operating
    system always have larger values for these macros. If for any
    reason the version cannot be analyzed by the compiler, then the
    corresponding predefined macro is defined but has the value of
    0. Releases of the compiler prior to Version 5.0 do not define
    these macros, so you can distinguish earlier compiler versions by
    checking to determine if the __DECCXX_VER macro is defined.

    The following example tests for C++ 5.1 or higher:

    #ifdef __DECCXX_VER
        #if __DECCXX_VER >= 50100000
            / *Code */
        #endif
    #endif

    The following tests for OpenVMS Version 6.2 or higher:

    #ifdef __VMS_VER
        #if __VMS_VER >= 60200000
            /* code */
        #endif
    #endif

    The following table shows the macro names for the listed command-
    line qualifiers.

    Command-line Option         Macro Name

    /ASSUME=GLOBAL_ARRAY_NEW    __GLOBAL_ARRAY_NEW
    /ASSUME=STDNEW              __STDNEW
    /DEFINE=__FORCE_            __FORCE_INSTANTIATIONS
    INSTANTATIONS
    /EXCEPTIONS                 __EXCEPTIONS
    /IEEE_MODE                  _IEEE_FP
    /IMPLICIT_INCLUDE           __IMPLICIT_INCLUDE_ENABLED
    /L_DOUBLE_SIZE              __X_FLOAT
    /MODEL=ANSI                 __MODEL_ANSI
    /MODEL=ARM                  __MODEL_ARM
    /PURE_CNAME                 __PURE_CNAME, __HIDE_FORBIDDEN_NAMES
    /ROUNDING_MODE              __BIASED_FLT_ROUNDS
    /RTTI                       __RTTI
    /STANDARD=RELAXED           __STD_ANSI, __NOUSE_STD_IOSTREAM
    /STANDARD=ANSI              __STD_ANSI, __NOUSE_STD_IOSTREAM
    /STANDARD=ARM               __STD_ARM, __NOUSE_STD_IOSTREAM
    /STANDARD=GNU               __STD_GNU, __NOUSE_STD_IOSTREAM
    /STANDARD=MS                __STD_MS, __NOUSE_STD_IOSTREAM
    /STANDARD=STRICT_ANSI       __STD_STRICT_ANSI,
                                __USE_STD_IOSTREAM, __PURE_CNAME
                                __HIDE_FORBIDDEN_NAMES
    /STANDARD=STRICT_ANSI       __STD_STRICT_ANSI_ERRORS
    /WARNINGS=ANSI_ERRORS
                                __PURE_CNAME, __HIDE_FORBIDDEN_NAMES
    /STANDARD=LATEST            __STD_STRICT_ANSI,
                                __USE_STD_IOSTREAM, __PURE_CNAME
                                __HIDE_FORBIDDEN_NAMES
    /STANDARD=LATEST            __STD_STRICT_ANSI_ERRORS
    /WARNINGS=ANSI_ERRORS
                                __PURE_CNAME, __HIDE_FORBIDDEN_NAMES
    /USING=STD                  __IMPLICIT_USING_STD

  4 - Release Notes

    The release notes for C++ are contained in the following files:

     SYS$HELP:CXX.RELEASE_NOTES
     SYS$HELP:CXX_RELEASE_NOTES.PS

    You can type or print these files to read the release notes
    information.

  5 - Class Library

    To access help on the C++ Class Library, enter the following
    command at the DCL command prompt:

    $ HELP CXXL

  6 - Standard Library

    To access help on the C++ Standard Library, enter the following
    command at the DCL command prompt:

    $ HELP CXXLSTD

  7 - Customer Support

    Premium support is available on a per-incident basis

    http://www.hp.com/hps/perevent/pv_software.html

    and annual contracts

    http://www.hp.com/hps/os/os_openvms.html

    from HP Services in the US and some other countries. In the US
    and Canada, call, toll-free, 1-800-354-9000. In other countries,
    support phone numbers are available on the web at:

    http://welcome.hp.com/country/us/en/wwcontact.html

    Free support is limited to bug reports that can be sent to

    compaq_cxx.bugs@hp.com

    Send a complete but short example reproducing the problem,
    including the following:

    o  Compiler and operating system versions

    o  All necessary sources (such as INCLUDE files and module
       sources)

    o  Data files

    o  Commands used to compile, link and run the program

    o  Expected results and incorrect results obtained

    Please try to reduce the problem to as small a source
    as possible, because we may be unable to diagnose large
    applications.

    We answer most quickly those problem reports that include a small
    but complete reproducible example, along with descriptions of
    the compile and link options used and the exact text of any
    diagnostic messages or other incorrect results. Reports that
    include only program fragments or involve very large applications
    generally will not be accepted.

    Please note that this is not a "programming consulting service"
    and that you should have clear evidence of a product problem
    before contacting us. If you need consulting services, please
    contact HP Services.

  8 - CXXLINK

    To access help on the CXXLINK facility, enter the following
    command at the DCL command prompt:

    $ HELP CXXLINK

  9 - CXXDEMANGLE

    To access help on the CXXDEMANGLE facility, enter the following
    command at the DCL command prompt:

    $ HELP CXXDEMANGLE
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