Re: backtrace

On Thu, 31 Aug 2000, Zeev Suraski wrote: > At 21:22 31-08-00, Sascha Schumann wrote: > >On Thu, 31 Aug 2000, Zeev Suraski wrote: > > > > > At 18:33 31-08-00, Sascha Schumann wrote: > > > >On Thu, 31 Aug 2000, Stanislav Malyshev wrote: > > > > > > > > > j>> called with a null list of var_args, which is causing it to barf. > > > > > j>> Problem is, the variable orig_args is being cleared on line 369 > > > > > j>> (va_end()), and > > > > > j>> then being reused on line 444. > > > > > > > > > > Sorry, don't see any va_end in current CVS. > > > > > > > > The old_args stuff was removed some weeks ago (if we are > > > > talking about main/main.c). The author of the original code > > > > did not seem to be aware of the correct va_args use. > > > > > > Actually, the original version was quite alright, except for under very > > > weird platforms, which define va_list as a type that cannot be copied > > > (probably some sort of an array). > > > > It was not necessary at all to copy it. That is where I saw > > the basic misunderstanding. A va_list can be traversed > > multiple times without copying it. > > A va_list cannot be traversed multiple times, which is why the code was > originally there (I think). The standard says otherwise. > Many platforms that define va_list as a simple pointer, reset it to NULL on > va_end(), which makes it useless afterwards. That behaviour is in conformance with ISO C99, SuS II and the upcoming SuS III (successor of POSIX). "void va_end(va_list ap) [..] The va_end macro may modify ap so that it is no longer usable (without being reinitialized by the va_start or va_copy macro). [..]" Note the part about reinitialization. - Sascha