Writes data to a stream.
#include <stdio.h>
size_t fwrite( const void *buffer, size_t size, size_t count, FILE *stream );
| buffer | Pointer to data to be written | |
| size | Item size in bytes | |
| count | Maximum number of items to be written | |
| stream | Pointer to FILE structure |
The fwrite function writes up to count items, of length size each, from buffer to the output stream. The file pointer associated with stream (if there is one) is incremented by the number of bytes actually written.
If stream is opened in text mode, each carriage return is replaced with a carriage-return–line-feed pair. The replacement has no effect on the return value.
The fwrite function returns the number of full items actually written, which may be less than count if an error occurs. Also, if an error occurs, the file-position indicator cannot be determined.
Standards:ANSI, UNIX
16-Bit:DOS, QWIN, WIN, WIN DLL
32-Bit:DOS32X
/* FREAD.C: This program opens a file named FREAD.OUT and writes 25
* characters to the file. It then tries to open FREAD.OUT and
* read in 25 characters. If the attempt succeeds, the program
* displays the number of actual items read.
*/
#include <stdio.h>
void main( void )
{
FILE *stream;
char list[30];
int i, numread, numwritten;
/* Open file in text mode: */
if( (stream = fopen( "fread.out", "w+t" )) != NULL )
{
for ( i = 0; i < 25; i++ )
list[i] = 'z' - i;
/* Write 25 characters to stream */
numwritten = fwrite( list, sizeof( char ), 25, stream );
printf( "Wrote %d items\n", numwritten );
fclose( stream );
}
else
printf( "Problem opening the file\n" );
if( (stream = fopen( "fread.out", "r+t" )) != NULL )
{
/* Attempt to read in 25 characters */
numread = fread( list, sizeof( char ), 25, stream );
printf( "Number of items read = %d\n", numread );
printf( "Contents of buffer = %.25s\n", list );
fclose( stream );
}
else
printf( "Was not able to open the file\n" );
}
Wrote 25 items
Number of items read = 25
Contents of buffer = zyxwvutsrqponmlkjihgfedcb