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compat_vasprintf.c
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compat_vasprintf.c
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#include "config.h"
#if HAVE_VASPRINTF
int dummy;
#else
/* $Id: compat_vasprintf.c,v 1.3 2015/10/06 18:32:19 schwarze Exp $ */
/*
* Copyright (c) 2015 Ingo Schwarze <[email protected]>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
* This fallback implementation is not efficient:
* It does the formatting twice.
* Short of fiddling with the unknown internals of the system's
* printf(3) or completely reimplementing printf(3), i can't think
* of another portable solution.
*/
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
int
vasprintf(char **ret, const char *format, va_list ap)
{
char buf[2];
va_list ap2;
int sz;
va_copy(ap2, ap);
sz = vsnprintf(buf, sizeof(buf), format, ap2);
va_end(ap2);
if (sz != -1 && (*ret = malloc(sz + 1)) != NULL) {
if (vsnprintf(*ret, sz + 1, format, ap) == sz)
return sz;
free(*ret);
}
*ret = NULL;
return -1;
}
#endif