1#include "stdio_impl.h"
 2
 3/* The behavior of this function is undefined except when it is the first
 4 * operation on the stream, so the presence or absence of locking is not
 5 * observable in a program whose behavior is defined. Thus no locking is
 6 * performed here. No allocation of buffers is performed, but a buffer
 7 * provided by the caller is used as long as it is suitably sized. */
 8
 9int setvbuf(FILE *restrict f, char *restrict buf, int type, size_t size)
10{
11	f->lbf = EOF;
12
13	if (type == _IONBF) {
14		f->buf_size = 0;
15	} else if (type == _IOLBF || type == _IOFBF) {
16		if (buf && size >= UNGET) {
17			f->buf = (void *)(buf + UNGET);
18			f->buf_size = size - UNGET;
19		}
20		if (type == _IOLBF && f->buf_size)
21			f->lbf = '\n';
22	} else {
23		return -1;
24	}
25
26	f->flags |= F_SVB;
27
28	return 0;
29}