Error: multiple definition of

[TheExDeus]

I ALWAYS get errors like this with ENIGMA when I am making something. And I am never able to fix these. Google search revelaed that is means what it says it means - I have multiple definitions of some structure or the like. This problem arrises when I include the first.h file (where structs are declared) into another second.h file and then include that second.h inside a project where I inclued the first.h then I will have two declarations of the same thing. The twist though, is that I DON'T. I think ENIGMA does include it somewhere, but I don't. The file structure:
include.h
main_code.cpp
I have #include "include.h" inside main_code.cpp. That is it. I don't include that "include.h" anywhere else. This is an extension though, so I have this in the Makefile:

SOURCES += $(wildcard Universal_System/Extensions/SomeExtension/main_code.cpp)
ifeq ($(PLATFORM), Win32)
   LDLIBS += $(wildcard Universal_System/Extensions/SomeExtension/libs/*.a)
endif

This is it.

So for the love of anything - WHY the hell it trows this error? I had this problem when I added surfaces as well. That is why it took me more than a year to add that god damn FBO support.

edit: It shows:
.eobjs/Windows/Windows/Run/SHELLmain.o:SHELLmain.cpp:(.text+0x6): first defined here
So ENIGMA includes the include.h inside the SHELLmain.cpp even when I don't ask it to? It would be fine if it did that and I could leave out #include "include.h" in the .cpp, but then it errors that I don't have struct's defined. So I either don't have them defined, or I have defined them twice. I don't really have a choice there.

edit2: I also tried "include guard" technique. So I had:
#ifndef MYFILE_H
#define MYFILE_H
//contents of include.h
#endif
And it still had the same error. This doesn't even make sense, because I can't have included it twice in this case.

[TheExDeus]

......................

[Josh @ Dreamland]

It doesn't matter if you guard it if you are including the header from two source files.
Don't declare globals in headers, except with extern.
Don't implement functions in headers unless they are static and/or inline.

[TheExDeus]

It doesn't matter if you guard it if you are including the header from two source files.

But where do I do this? I have only one place I include it (I have only one .cpp file). I think ENIGMA includes the header somewhere as well as part of the extensions system, and that is what causes me the trouble.

Don't declare globals in headers, except with extern.

I don't declare any globals in headers.

Don't implement functions in headers unless they are static and/or inline.

I do have functions there for structs. Like grid::grid(). I will try to move them in the .cpp and see what happens.

edit: That did it. I don't know what else includes the header, but that was frustrating.

[Rusky]

Surround the contents of the header file with

Code: [Select]

#ifndef HEADER_NAME_H
#define HEADER_NAME_H

Code: [Select]

#endif...just in the general case.

[TheExDeus]

That is what I did previously. Didn't help. For some unknown reason it still got included twice.

[Rusky]

In addition to not implementing non-static, non-inline functions in headers, of course.

If a function like that is in a header file it will exist in multiple object files and the linker will complain.

That's different from being #included twice.