Hi,
I'm trying to help a guy using Python. From Python on a PPC Mac, he
is trying to call printf
in the standard C shared library with a format string, an int, and
some doubles. I'm thinking
that the calling sequence from python back into the real C code is
not going to call printf
properly because, as I recall, to call printf properly, the compiler
must see the prototype so
it knows to actually push the arguments and not pass them in
registers. So, I tried to
demonstrate this to him by writing the following program:
int main()
{
printf("int=%d double=%f\n", 5, 8.2);
return 0;
}
(note, I'm not including anything.) When I compile it I get this:
make -k dog && ./dog
cc dog.c -o dog
dog.c: In function 'main':
dog.c:3: warning: incompatible implicit declaration of built-in
function 'printf'
int=5 double=8.200000
So, somehow, gcc "knows" about printf (I guess that is what the
warning is
telling me). Can I tell gcc to "forget" and go ahead and produce
whatever
code its best guess is.
Or... can someone confirm that to call functions that takes a
variable number
of mixed arguments, the compiler has to see a prototype in order to
produce
working code.
Perry Smith ( pedz@xxxxxxxxxxxxxxxx )
Ease Software, Inc. ( http://www.easesoftware.com )
Low cost SATA Disk Systems for IBMs p5, pSeries, and RS/6000 AIX systems
