1 /* sprintf_alloc.c -- like sprintf with memory allocation
5 Copyright (C) 2001 University of Southern California
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
21 #include "sprintf_alloc.h"
23 int sprintf_alloc(char **str
, const char *fmt
, ...)
30 fprintf(stderr
, "Null string pointer passed to sprintf_alloc\n");
34 fprintf(stderr
, "Null fmt string passed to sprintf_alloc\n");
38 /* On x86_64 systems, any strings over 100 were segfaulting.
39 It seems that the ap needs to be reinitalized before every
40 use of the v*printf() functions. I pulled the functionality out
41 of vsprintf_alloc and combined it all here instead.
45 /* ripped more or less straight out of PRINTF(3) */
47 if ((new_str
= malloc(size
)) == NULL
)
53 n
= vsnprintf (new_str
, size
, fmt
, ap
);
55 /* If that worked, return the size. */
56 if (n
> -1 && n
< size
)
58 /* Else try again with more space. */
59 if (n
> -1) /* glibc 2.1 */
60 size
= n
+1; /* precisely what is needed */
62 size
*= 2; /* twice the old size */
63 new_str
= realloc(new_str
, size
);
64 if (new_str
== NULL
) {
72 return -1; /* Just to be correct - it probably won't get here */