fwrite(3C) Standard C Library Functions 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 successfully 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 different processor.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Interface Stability |Standard |
+-----------------------------+-----------------------------+
|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), attributes(5), standards(5)
SunOS 5.10 24 Jul 2002 fwrite(3C)