Mercurial > hg > octave-lojdl > gnulib-hg
changeset 5297:c0fb011695d9
Add comment about preallocated buffer. Suggested by Simon Josefsson.
author | Bruno Haible <bruno@clisp.org> |
---|---|
date | Fri, 01 Oct 2004 20:42:15 +0000 |
parents | 41b2af35134e |
children | 45c149f6b6b9 |
files | lib/vasnprintf.h |
diffstat | 1 files changed, 19 insertions(+), 2 deletions(-) [+] |
line wrap: on
line diff
--- a/lib/vasnprintf.h +++ b/lib/vasnprintf.h @@ -1,5 +1,5 @@ /* 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 General Public License as published by @@ -47,7 +47,24 @@ 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)