NAME

       fwrite - binary output

SYNOPSIS

       #include <stdio.h>

       size_t fwrite(const void *restrict ptr, size_t size, size_t nitems,
              FILE *restrict stream);

DESCRIPTION

       The  fwrite() function shall write, from the array pointed to by ptr, up to nitems elements whose size is
       specified by size, to the stream pointed to by stream.  For each object, size calls shall be made to  the
       fputc()  function,  taking  the  values  (in order) from an array of unsigned char exactly overlaying the
       object. The file-position indicator for the stream (if defined) shall be advanced by the number of  bytes
       successfully  written.  If  an  error  occurs, the resulting value of the file-position indicator for the
       stream is unspecified.

       The st_ctime and st_mtime fields of the file shall be marked for update between the successful  execution
       of fwrite() and the next successful completion of a call to fflush() or fclose() on the same stream, or a
       call to exit() or abort().

RETURN VALUE

       The  fwrite()  function  shall return the number of elements successfully written, which may be less than
       nitems if a write error is encountered. If size or nitems is 0, fwrite() shall return 0 and the state  of
       the  stream  remains  unchanged.  Otherwise,  if a write error occurs, the error indicator for the stream
       shall be set,    and errno shall be set to indicate the error.

ERRORS

       Refer to fputc() .

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       Because of possible differences in element length and byte ordering, files  written  using  fwrite()  are
       application-dependent,  and  possibly  cannot  be read using fread() by a different application or by the
       same application on a different processor.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       ferror() ,  fopen()  ,  printf()  ,  putc()  ,  puts()  ,  write()  ,  the  Base  Definitions  volume  of
       IEEE Std 1003.1-2001, <stdio.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition,
       Standard  for  Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers,
       Inc and The Open Group. In the event of any discrepancy between this version and the  original  IEEE  and
       The  Open  Group  Standard,  the  original  IEEE and The Open Group Standard is the referee document. The
       original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

IEEE/The Open Group                                   2003                                             FWRITE(P)