ref: d75c01ac6bb53fc48551d716458abf428c2687c6
dir: /lib/c/_flsbuf.c/
#include <errno.h>
#include <stdio.h>
#include "syscall.h"
int
_flsbuf(FILE *fp)
{
int lnbuf = fp->flags & _IOLBF;
size_t cnt;
cnt = ((lnbuf) ? fp->lp : fp->wp) - fp->buf;
if (_write(fp->fd, fp->buf, cnt) != cnt) {
fp->flags |= _IOERR;
return EOF;
}
fp->rp = fp->wp = fp->buf;
return 0;
}