On Mon, Dec 13, 2010 at 1:10 AM, Tom C <
mel0torme@gmail.com> wrote:
> I was attempting to build FreeSwitch on a Dockstar running Debian Squeeze,
> and ran into the sofia.c logger() compile problem as described here:
>
http://jira.freeswitch.org/browse/FS-802
>
> The offered solution was to downgrade GCC, but being a Linux newbie, I
> didn't know how to do that. So I decided to figure out what the problem
> really is.
>
> After learning waaaay too much about va_list, I see that the logger()
> function in sofia.c assumes that va_list will always be a pointer. But on
> different platforms, va_list can be an array or a struct. On the Dockstar
> (with Debian Squeeze and GCC 4.4), va_list is apparently a struct.
>
> I made the following modifications to logger() to make it truly portable,
> and it compiles and runs fine on my DockStar, my Debian Lenny x86. (My
> Windows build is having bigger problems.) But I'm no C guru, so someone
> needs to thoroughly examine my code before anyone else takes it as gospel.
> Am I actually checking what needs to be checked with the va_arg() macro?
> Changing it to if(1) worked too, after all.
>
>
> ORIGINAL logger() in sofia.c, to make it easy to see what I changed.
> static void logger(void *logarg, char const *fmt, va_list ap)
> {
> /* gcc 4.4 gets mad at us for testing if (ap) so let's try to work around
> it....*/
> void *ap_ptr = (void *) (intptr_t) ap; //Error now occurs here, because ap
> is a struct.
> if (!fmt) return;
> if (ap_ptr) { //Error used to occur here, before attempted fix above.
> switch_log_vprintf(SWITCH_CHANNEL_LOG_CLEAN,
> mod_sofia_globals.tracelevel, fmt, ap);
> } else {
> switch_log_printf(SWITCH_CHANNEL_LOG_CLEAN, mod_sofia_globals.tracelevel,
> "%s", fmt);
> }
> }
>
>
> My MODIFIED logger() function, additions and changes labelled with DOCKSTAR:
>
> static
>
> void logger(void *logarg, char const *fmt, va_list ap)
> {
> va_list temp_ap; //DOCKSTAR: Added line (replacing previous ap_ptr cast).
>
> if (!fmt) return;
>
> va_copy(temp_ap, ap); //DOCKSTAR: Added Line. Make copy of "ap" so va_arg()
> macro doesn't move pointer.
>
> if (va_arg(temp_ap, int)) { //DOCKSTAR: Modified, get first argument from
> ap, check non-null.
> switch_log_vprintf(SWITCH_CHANNEL_LOG_CLEAN,
> mod_sofia_globals.tracelevel, fmt, ap);
> } else {
> switch_log_printf(SWITCH_CHANNEL_LOG_CLEAN,
> mod_sofia_globals.tracelevel, "%s", fmt);
> }
>
> va_end(temp_ap); //DOCKSTAR: Added line. Release our copy of "ap".
> }
>