The following example reads a single element from the fp stream into
the array pointed to by buf.

#include <stdio.h>
...
size_t elements_read;
char buf[100];
FILE *fp;
...
elements_read = fread(buf, sizeof(buf), 1, fp);
...

If a read error occurs, elements_read will be zero but the number of
bytes read from the stream could be anything from zero to sizeof(buf)-1.

The following example reads multiple single-byte elements from the fp
stream into the array pointed to by buf.

#include <stdio.h>
...
size_t bytes_read;
char buf[100];
FILE *fp;
...
bytes_read = fread(buf, 1, sizeof(buf), fp);
...

If a read error occurs, bytes_read will contain the number of bytes
read from the stream.