summaryrefslogtreecommitdiff
path: root/src/stdio/ungetc.c
blob: 180673a47663ad57b11d3e6525c35cc23858939a (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
#include "stdio_impl.h"

int ungetc(int c, FILE *f)
{
	if (c == EOF) return c;

	FLOCK(f);

	if (!f->rpos) __toread(f);
	if (!f->rpos || f->rpos <= f->buf - UNGET) {
		FUNLOCK(f);
		return EOF;
	}

	*--f->rpos = c;
	f->flags &= ~F_EOF;

	FUNLOCK(f);
	return c;
}