Same as the fputc function, except used only within a scope
    protected by flockfile and funlockfile.
    This function is OpenVMS Alpha and Integrity servers only.
    Format
      #include  <stdio.h>
      int fputc_unlocked  (int character, FILE *file_ptr);
1 – Arguments
 character
    The character to be written. An object of type int.
 file_ptr
    A file pointer.
2 – Description
    See the putc_unlocked macro.
    Compiling with the __UNIX_PUTC macro defined enables an
    optimization that uses a faster, inlined version of this
    function.
    See also flockfile, ftrylockfile, and funlockfile.
3 – Return Values
    n                  The returned character.
    EOF                Indicates the end-of-file or an error.