guile/lib/vasnprintf.h

/* vsprintf with automatic memory allocation.
   Copyright (C) 2002-2004, 2007-2012 Free Software Foundation, Inc.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU Lesser General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public License along
   with this program; if not, write to the Free Software Foundation,
   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */

#ifndef _VASNPRINTF_H
#define _VASNPRINTF_H

/* Get va_list.  */
#include <stdarg.h>

/* Get size_t.  */
#include <stddef.h>

/* The __attribute__ feature is available in gcc versions 2.5 and later.
   The __-protected variants of the attributes 'format' and 'printf' are
   accepted by gcc versions 2.6.4 (effectively 2.7) and later.
   We enable _GL_ATTRIBUTE_FORMAT only if these are supported too, because
   gnulib and libintl do '#define printf __printf__' when they override
   the 'printf' function.  */
#if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 7)
# define _GL_ATTRIBUTE_FORMAT(spec) __attribute__ ((__format__ spec))
#else
# define _GL_ATTRIBUTE_FORMAT(spec) /* empty */
#endif

#ifdef __cplusplus
extern "C" {
#endif

/* Write formatted output to a string dynamically allocated with malloc().
   You can pass a preallocated buffer for the result in RESULTBUF and its
   size in *LENGTHP; otherwise you pass RESULTBUF = NULL.
   If successful, return the address of the string (this may be = RESULTBUF
   if no dynamic memory allocation was necessary) and set *LENGTHP to the
   number of resulting bytes, excluding the trailing NUL.  Upon error, set
   errno and return NULL.

   When dynamic memory allocation occurs, the preallocated buffer is left
   alone (with possibly modified contents).  This makes it possible to use
   a statically allocated or stack-allocated buffer, like this:

          char buf[100];
          size_t len = sizeof (buf);
          char *output = vasnprintf (buf, &len, format, args);
          if (output == NULL)
            ... error handling ...;
          else
            {
              ... use the output string ...;
              if (output != buf)
                free (output);
            }
  */
#if REPLACE_VASNPRINTF
# define asnprintf rpl_asnprintf
# define vasnprintf rpl_vasnprintf
#endif
extern char * asnprintf (char *resultbuf, size_t *lengthp, const char *format, ...)
       _GL_ATTRIBUTE_FORMAT ((__printf__, 3, 4));
extern char * vasnprintf (char *resultbuf, size_t *lengthp, const char *format, va_list args)
       _GL_ATTRIBUTE_FORMAT ((__printf__, 3, 0));

#ifdef __cplusplus
}
#endif

#endif /* _VASNPRINTF_H */