Associates a file pointer with a file descriptor returned by an
    open, creat, dup, dup2, or pipe function.

    Format

      #include  <stdio.h>

      FILE *fdopen  (int file_desc, char *a_mode);

1 - Arguments

 file_desc

    The file descriptor returned by open, creat, dup, dup2, or pipe.

 a_mode

    The access mode indicator. See the fopen function for a
    description. Note that the access mode specified must agree
    with the mode used to originally open the file. This includes
    binary/text access mode ("b" mode on fdopen and the "ctx=bin"
    option on creat or open).

2 - Description

    The fdopen function allows you to access a file, originally
    opened by one of the UNIX I/O functions, with Standard I/O
    functions. Ordinarily, a file can be accessed by either a file
    descriptor or by a file pointer, but not both, depending on the
    way you open it.

3 - Return Values

    pointer            Indicates that the operation has succeeded.
    NULL               Indicates that an error has occurred.