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Re: [c++] warn if NULL is passed through varargs
On Oct 11, 2002, Jason Merrill <jason@redhat.com> wrote:
> On 09 Oct 2002 16:57:37 -0300, Alexandre Oliva <aoliva@redhat.com> wrote:
>> The problem in C++ is very real. __null doesn't decay to a
>> pointer-wide integer type in varargs, and this has caused a run-time
>> error in an application, which got me into writing this patch.
> Please elaborate. It's certainly intended to decay to a pointer-wide
> integer.
I see its type is a POINTER_SIZE integer type, but that's not the only
kind of pointer in C++. NULL also stands for a NULL pointer-to-member
constant, and that's wider. It's this ambiguity that we should warn
about.
That said, all I know about the problem was that gnomemeeting, being
compiled to a 64-bit target, passed NULL as the last argument to a
varargs function, and it crashed, but adding a cast to (glong) fixed
it. I'll try to find out which target it was, which exact version of
gcc was being used, and whether g++'s definition of NULL was in
effect.
--
Alexandre Oliva Enjoy Guarana', see http://www.ic.unicamp.br/~oliva/
Red Hat GCC Developer aoliva@{redhat.com, gcc.gnu.org}
CS PhD student at IC-Unicamp oliva@{lsd.ic.unicamp.br, gnu.org}
Free Software Evangelist Professional serial bug killer