Could use some help with variable length argument lists

[Ben Smithurst]

Bill Moran wrote:

>     char **format, **errmsg;
> 
>     va_start(ap, message);
>     if (level <= LOGLEVEL) {
>         asprintf(format, "PID %d: %s", getpid(), message);
...
> Doesn't seem too difficult, right?  However, if I call the function
> from elsewhere in my application like this:
> 
> _log(1, "Log test");
> 
> I get a coredump!  gdb complains that message is "out of bounds"
> on the line "asprintf(format, "PID %d: %s", getpid(), message);"

are you sure it isn't the format variable causing the problem?  It's
a while since I've used asprintf() but from memory you should write
something more like

char *format;
...
asprintf(&format, "PID %d: %s", getpid(), message);

Your code above is passing format uninitialized (you should have got a
compile time warning about that).

Or maybe I'm misunderstanding something. :-)

-- 
Ben Smithurst / ben at FreeBSD.org                 FreeBSD: The Power To Serve
                                                    http://www.FreeBSD.org/
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