Returns the description of a mapping, corresponding to specified
    property, that can later be used in a call to towctrans.

    Format

      #include  <wctype.h>

      wctrans_t wctrans  (const char *property);

1 - Argument

 property

    The name of the mapping. The following property names are defined
    for all locales:

    o  "toupper"

    o  "tolower"

    Additional property names may also be defined in the LC_CTYPE
    category of the current locale.

2 - Description

    The wctrans function constructs a value with type wctrans_t that
    describes a mapping between wide characters identified by the
    property argument.

    See also towctrans.

3 - Return Values

    nonzero            According to the LC_CTYPE category of the
                       current program locale, the string specified
                       as a property argument is the name of an
                       existing character mapping. The value returned
                       can be used in a call to the towctrans
                       function.
    0                  Indicates an error. The property argument
                       does not identify a character mapping in the
                       current program's locale.