fwrite - binary output size_t fwrite(const void *restrict ptr,
size_t size, size_t nitems, FILE *restrict stream); [CX] The
functionality described on this reference page is aligned with
the ISO C standard. Any conflict between the requirements
described here and the ISO C standard is unintentional. This
volume of IEEE Std 1003.1-2001 defers to the ISO C standard. 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. [CX] The st_ctime and st_mtime
fields of the file shall be marked for update between the
successful execution of fwrit