1 /* vsprintf with automatic memory allocation. 2 Copyright (C) 2002-2004, 2012, 2015-2016 Free Software Foundation, Inc. 3 4 This program is free software: you can redistribute it and/or modify 5 it under the terms of the GNU Lesser General Public License as published by 6 the Free Software Foundation; either version 2.1 of the License, or 7 (at your option) any later version. 8 9 This program is distributed in the hope that it will be useful, 10 but WITHOUT ANY WARRANTY; without even the implied warranty of 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 GNU Lesser General Public License for more details. 13 14 You should have received a copy of the GNU Lesser General Public License 15 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 16 17 #ifndef _VASNPRINTF_H 18 #define _VASNPRINTF_H 19 20 /* Get va_list. */ 21 #include <stdarg.h> 22 23 /* Get size_t. */ 24 #include <stddef.h> 25 26 #ifndef __attribute__ 27 /* This feature is available in gcc versions 2.5 and later. */ 28 # if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 5) || __STRICT_ANSI__ 29 # define __attribute__(Spec) /* empty */ 30 # endif 31 /* The __-protected variants of 'format' and 'printf' attributes 32 are accepted by gcc versions 2.6.4 (effectively 2.7) and later. */ 33 # if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 7) 34 # define __format__ format 35 # define __printf__ printf 36 # endif 37 #endif 38 39 #ifdef __cplusplus 40 extern "C" { 41 #endif 42 43 /* Write formatted output to a string dynamically allocated with malloc(). 44 You can pass a preallocated buffer for the result in RESULTBUF and its 45 size in *LENGTHP; otherwise you pass RESULTBUF = NULL. 46 If successful, return the address of the string (this may be = RESULTBUF 47 if no dynamic memory allocation was necessary) and set *LENGTHP to the 48 number of resulting bytes, excluding the trailing NUL. Upon error, set 49 errno and return NULL. 50 51 When dynamic memory allocation occurs, the preallocated buffer is left 52 alone (with possibly modified contents). This makes it possible to use 53 a statically allocated or stack-allocated buffer, like this: 54 55 char buf[100]; 56 size_t len = sizeof (buf); 57 char *output = vasnprintf (buf, &len, format, args); 58 if (output == NULL) 59 ... error handling ...; 60 else 61 { 62 ... use the output string ...; 63 if (output != buf) 64 free (output); 65 } 66 */ 67 extern char * asnprintf (char *resultbuf, size_t *lengthp, const char *format, ...) 68 __attribute__ ((__format__ (__printf__, 3, 4))); 69 extern char * vasnprintf (char *resultbuf, size_t *lengthp, const char *format, va_list args) 70 __attribute__ ((__format__ (__printf__, 3, 0))); 71 72 #ifdef __cplusplus 73 } 74 #endif 75 76 #endif /* _VASNPRINTF_H */ 77