Thread: question about multible source files

I have two files. One is main.cpp and one is testfunction.cpp. testfunction.cpp has void testfunction()... main.cpp has int main()...

If I want to use testfunction from main it brings an error that no such function exists. But I am sure that testfunction.cpp is also getting compiled because if I add an error there I will get an compile error.

The only solution I found was to use main.h, main.cpp + testfunction.h and testfunction.cpp. All includes I need for main.cpp are included in main.h. testfunction.cpp includes first testfunctin.h and testfunction.h is getting included by main.h.

I think this could be a bad way. Is it?

Any other way to use testfunction from main.cpp?

That is not a bad way.
I would say if the functions declared in main h do not depend on anything from testfunction.h then the usual way would be that you remove the #include "testfunction.h" from main.h and include both main.h and testfunction.h into main.cpp.
One rule that I usually follow is that I never include any headers into another header that are not needed inside that header. I'd rather use forward declarations if that is enough.
Kurt

"main.h"??? <-- Obviously something wrong here.

If I want to use testfunction from main it brings an error that no such function exists. But I am sure that testfunction.cpp is also getting compiled because if I add an error there I will get an compile error.

Well, if there's something that won't compile, the compiler won't get to anything else after that error.

Be sure to use this with all your source files:

Code:

#ifndef _MYSOURCEFILENAME_H
#define _MYSOURCEFILENAME_H

/*  Your source file  */

#endif

*make* files would teach you a good way of keeping track of dependencies...

Basically:

wherever main is needs (#include "testfunction.cpp")

testfunction.cpp needs(#include "testfunction.h")

testfunction.h needs no other dependencies.

Originally Posted by entropyrexor

as an aside, there won't be multiple includes with the #ifndef directive

True no multiple includes. But multiply declared symbols. ( linker errors )
Kurt

True dat ZuK.

I was only trying to get sept's program to compile with the least bit of confusion, i didn't mean to advocate such sloppiness, sorry guys