source: bootcd/isolinux/syslinux-6.03/com32/lib/fwrite.c

/*
 * fwrite.c
 */

#include <errno.h>
#include <unistd.h>
#include <stdio.h>

size_t _fwrite(const void *buf, size_t count, FILE * f)
{
    size_t bytes = 0;
    ssize_t rv;
    const char *p = buf;

    while (count) {
        rv = write(fileno(f), p, count);
        if (rv == -1) {
            if (errno == EINTR || errno == EAGAIN)
                continue;
            else
                break;
        } else if (rv == 0) {
            break;
        }

        p += rv;
        bytes += rv;
        count -= rv;
    }

    return bytes;
}