Make it usable by a C++ compiler.

[gnulib.git] / lib / vasnprintf.h

diff --git a/lib/vasnprintf.h b/lib/vasnprintf.h
index 65f1bc1..894008c 100644 (file)
--- a/lib/vasnprintf.h
+++ b/lib/vasnprintf.h
@@ -1,20 +1,19 @@
 /* vsprintf with automatic memory allocation.
-   Copyright (C) 2002-2003 Free Software Foundation, Inc.
+   Copyright (C) 2002-2004 Free Software Foundation, Inc.
 
-   This program is free software; you can redistribute it and/or modify it
-   under the terms of the GNU Library General Public License as published
-   by the Free Software Foundation; either version 2, or (at your option)
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU 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
-   Library General Public License for more details.
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
 
-   You should have received a copy of the GNU Library General Public
-   License along with this program; if not, write to the Free Software
-   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
-   USA.  */
+   You should have received a copy of the GNU 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
@@ -48,7 +47,24 @@ extern "C" {
    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.  */
+   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);
+            }
+  */
 extern char * asnprintf (char *resultbuf, size_t *lengthp, const char *format, ...)
        __attribute__ ((__format__ (__printf__, 3, 4)));
 extern char * vasnprintf (char *resultbuf, size_t *lengthp, const char *format, va_list args)