linkage error with non-member functions

Question

------------------blah.h------------------------
#pragma once
namespace SomeNamespace{
 static void someMethod(){}
}
-----------------blah.c--------------------------
#include “blah.h”
int main(int argc, char**argv){
 SomeNamespace::someMethod();
return 0;
}

The above works fine but if I omit ‘static’ I get:

>stdafx.obj : error LNK2005: "void __cdecl SomeNamespace::someMethod(void)"
(?someMethod@SomeNamespace@@YAXXZ) already defined in Dude.obj
1>...\Debug\Dude.exe : fatal error LNK1169: one or more multiply defined
symbols found

I read about what ‘static’ does to non-member functions – http://www.velocityreviews.com/forums/t284052-static-functions.html …

...give it internal linkage so that it won't be visible outside the compilation unit -- i.e., (over-simplified) the linker will not see it. This use of 'static' is deprecated, and imposes the limitation that the function cannot be used as a template argument. The modern way is to instead place the function in an anonymous namespace…

But the thing is I want the method to be exposed. What am I doing wrong?

Answer 1

• Declare your function in .h (i.e. void foo(int x);)
• Define then in .c (i.e. void foo(int x) { ... })