[LLVMdev] Request for help: why does the program link correctly?

[Jim Grosbach]

Linking typically doesn’t pay attention to types, just to symbol names. The symbol is indeed defined, so it links OK. This is one of the problems name mangling helps solve in C++.

-Jim

> On Jul 1, 2015, at 10:09 PM, Soumitra Chatterjee <soumitra at hp.com> wrote:
> 
> Hi,
> 	I am a bit stumped on the following case, and hopefully missing something very basic. Can someone please help me understand why the following is allowed to link correctly?
> 
> $ cat -n main.c
>     1  extern void foo();
>     2
>     3  int main() { foo(); }
> 
> $ cat -n def.c
>     1  int foo = 99;
> 
> $ clang main.c def.c ; echo $?
> 0
> 
> I guess the answer depends on why is 'main.c::foo' not marked as func?
> 
> $ clang -c main.c def.c
> $ readelf -s main.o def.o | grep foo
>     9: 0000000000000000     0 NOTYPE  GLOBAL DEFAULT  UND foo
>     7: 0000000000000000     4 OBJECT  GLOBAL DEFAULT    2 foo
> 
> Thanks,
> Soumitra
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