lib/vasnprintf.h

   1 /* vsprintf with automatic memory allocation.
   2    Copyright (C) 2002-2004 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 General Public License as published by
   6    the Free Software Foundation; either version 2, or (at your option)
   7    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 General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License along
  15    with this program; if not, write to the Free Software Foundation,
  16    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  17
  18 #ifndef _VASNPRINTF_H
  19 #define _VASNPRINTF_H
  20
  21 /* Get va_list.  */
  22 #include <stdarg.h>
  23
  24 /* Get size_t.  */
  25 #include <stddef.h>
  26
  27 #ifndef __attribute__
  28 /* This feature is available in gcc versions 2.5 and later.  */
  29 # if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 5) || __STRICT_ANSI__
  30 #  define __attribute__(Spec) /* empty */
  31 # endif
  32 /* The __-protected variants of `format' and `printf' attributes
  33    are accepted by gcc versions 2.6.4 (effectively 2.7) and later.  */
  34 # if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 7)
  35 #  define __format__ format
  36 #  define __printf__ printf
  37 # endif
  38 #endif
  39
  40 #ifdef  __cplusplus
  41 extern "C" {
  42 #endif
  43
  44 /* Write formatted output to a string dynamically allocated with malloc().
  45    You can pass a preallocated buffer for the result in RESULTBUF and its
  46    size in *LENGTHP; otherwise you pass RESULTBUF = NULL.
  47    If successful, return the address of the string (this may be = RESULTBUF
  48    if no dynamic memory allocation was necessary) and set *LENGTHP to the
  49    number of resulting bytes, excluding the trailing NUL.  Upon error, set
  50    errno and return NULL.
  51
  52    When dynamic memory allocation occurs, the preallocated buffer is left
  53    alone (with possibly modified contents).  This makes it possible to use
  54    a statically allocated or stack-allocated buffer, like this:
  55
  56           char buf[100];
  57           size_t len = sizeof (buf);
  58           char *output = vasnprintf (buf, &len, format, args);
  59           if (output == NULL)
  60             ... error handling ...;
  61           else
  62             {
  63               ... use the output string ...;
  64               if (output != buf)
  65                 free (output);
  66             }
  67   */
  68 extern char * asnprintf (char *resultbuf, size_t *lengthp, const char *format, ...)
  69        __attribute__ ((__format__ (__printf__, 3, 4)));
  70 extern char * vasnprintf (char *resultbuf, size_t *lengthp, const char *format, va_list args)
  71        __attribute__ ((__format__ (__printf__, 3, 0)));
  72
  73 #ifdef  __cplusplus
  74 }
  75 #endif
  76
  77 #endif /* _VASNPRINTF_H */