Blob


1 /* from mandoc, with tweaks */
2 /*
3 * Copyright (c) 2015 Ingo Schwarze <schwarze@openbsd.org>
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 *
17 * This fallback implementation is not efficient:
18 * It does the formatting twice.
19 * Short of fiddling with the unknown internals of the system's
20 * printf(3) or completely reimplementing printf(3), i can't think
21 * of another portable solution.
22 */
24 #include "../config.h"
26 #include <stdarg.h>
27 #include <stdio.h>
28 #include <stdlib.h>
30 int
31 vasprintf(char **ret, const char *format, va_list ap)
32 {
33 char buf[2];
34 va_list ap2;
35 int sz;
37 va_copy(ap2, ap);
38 sz = vsnprintf(buf, sizeof(buf), format, ap2);
39 va_end(ap2);
41 if (sz != -1 && (*ret = malloc(sz + 1)) != NULL) {
42 if (vsnprintf(*ret, sz + 1, format, ap) == sz)
43 return sz;
44 free(*ret);
45 }
46 *ret = NULL;
47 return -1;
48 }