incompatible function declaration

[Matthew Woehlke]

Michael wrote:
> gcc behaves differently for following program:
> 
> void foo2();
> int main() {
>    extern void foo(void);
>    foo();
>    foo2();
>    return 0;
> }
> 
> void foo2() {
>    foo();
> }
> 
> 
> compilation command:  gcc -c t1.c
> 
> result:
> 1. gcc 3.2.2 compiles successfully.
> 
> 2. gcc 4.0.3 gives following message:
> 
> t1.c: In function 'foo2':
> t1.c:10: error: incompatible implicit declaration of function 'foo'
> t1.c:3: error: previous implicit declaration of 'foo' was here
> 
> 
> question:
>    which one is more correct ? Is the error message too severe ?

I would say 4.0.3 is right... you made the declaration in a local scope 
so it does not apply to foo2(). When foo2() tries to call foo(), the 
default implicit prototype is 'int foo()', which is incompatible with 
the previous declaration as the error states.

-- 
Matthew
GDRLaH - Grin, Duck, and Run Like a Hippo! :-)