fwrite(3C)

NAME

     fwrite - binary output

SYNOPSIS

     #include <stdio.h>

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

DESCRIPTION

     The fwrite() function writes, 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  are made to the fputc(3C) 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) is 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 will be  marked
     for  update between the successful execution of fwrite() and
     the next successful completion of a call  to  fflush(3C)  or
     fclose(3C)  on  the  same  stream  or  a  call to exit(2) or
     abort(3C).

RETURN VALUES

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

ERRORS

     Refer to fputc(3C).

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(3C) by  a
     different  application  or by the same application on a dif-
     ferent processor.

ATTRIBUTES

     See attributes(5) for descriptions of the  following  attri-
     butes:

     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | MT-Level                    | MT-Safe                     |
    |_____________________________|_____________________________|

SEE ALSO

     write(2),  fclose(3C),  ferror(3C),  fopen(3C),   fread(3C),
     getc(3C),  gets(3C),  printf(3C), putc(3C), puts(3C), attri-
     butes(5)