1 c423c56e 2022-09-25 op /*
 2 c423c56e 2022-09-25 op  * Copyright (c) 2015 Ingo Schwarze <schwarze@openbsd.org>
 3 c423c56e 2022-09-25 op  *
 4 c423c56e 2022-09-25 op  * Permission to use, copy, modify, and distribute this software for any
 5 c423c56e 2022-09-25 op  * purpose with or without fee is hereby granted, provided that the above
 6 c423c56e 2022-09-25 op  * copyright notice and this permission notice appear in all copies.
 7 c423c56e 2022-09-25 op  *
 8 c423c56e 2022-09-25 op  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 9 c423c56e 2022-09-25 op  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10 c423c56e 2022-09-25 op  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11 c423c56e 2022-09-25 op  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12 c423c56e 2022-09-25 op  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13 c423c56e 2022-09-25 op  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14 c423c56e 2022-09-25 op  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15 c423c56e 2022-09-25 op  *
16 c423c56e 2022-09-25 op  * This fallback implementation is not efficient:
17 c423c56e 2022-09-25 op  * It does the formatting twice.
18 c423c56e 2022-09-25 op  * Short of fiddling with the unknown internals of the system's
19 c423c56e 2022-09-25 op  * printf(3) or completely reimplementing printf(3), i can't think
20 c423c56e 2022-09-25 op  * of another portable solution.
21 c423c56e 2022-09-25 op  */
22 c423c56e 2022-09-25 op 
23 c423c56e 2022-09-25 op #include <stdarg.h>
24 c423c56e 2022-09-25 op #include <stdio.h>
25 c423c56e 2022-09-25 op #include <stdlib.h>
26 c423c56e 2022-09-25 op 
27 c423c56e 2022-09-25 op int
28 c423c56e 2022-09-25 op vasprintf(char **ret, const char *format, va_list ap)
29 c423c56e 2022-09-25 op {
30 c423c56e 2022-09-25 op 	char	 buf[2];
31 c423c56e 2022-09-25 op 	va_list	 ap2;
32 c423c56e 2022-09-25 op 	int	 sz;
33 c423c56e 2022-09-25 op 
34 c423c56e 2022-09-25 op 	va_copy(ap2, ap);
35 c423c56e 2022-09-25 op 	sz = vsnprintf(buf, sizeof(buf), format, ap2);
36 c423c56e 2022-09-25 op 	va_end(ap2);
37 c423c56e 2022-09-25 op 
38 c423c56e 2022-09-25 op 	if (sz != -1 && (*ret = malloc(sz + 1)) != NULL) {
39 c423c56e 2022-09-25 op 		if (vsnprintf(*ret, sz + 1, format, ap) == sz)
40 c423c56e 2022-09-25 op 			return sz;
41 c423c56e 2022-09-25 op 		free(*ret);
42 c423c56e 2022-09-25 op 	}
43 c423c56e 2022-09-25 op 	*ret = NULL;
44 c423c56e 2022-09-25 op 	return -1;
45 c423c56e 2022-09-25 op }