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How to conditional compile main() in C?

I'm working on a small open source project in C where I'm trying to use a test framework with C (the framework is min_unit).

I have a foo.h file with prototypes, and foo.c, with the implementation.

In my test file, tests.c, I have 

#include "../test_framework/min_unit.h"
#include "foo.c"

... test cases ...

the problem is, because I have a main() function in foo.c (which I need to compile it), I can't compile tests.c because I get an error that states 

note: previous definition of ‘main’ was here
int main() {

My question is, is there a way to make it so that the main() function in foo.c is conditional, so that it does not compile when I'm running tests.c? It's just annoying to have to remove and add main over and over.

Solution

  • The easiest way to use conditional compilation is to use #ifdef statements. E.g., in foo.c you have:

    #ifdef NOT_TESTING //if a macro NOT_TESTING was defined
int main() {
    //main function here
}
#endif

    While in test.c, you put:

    #ifndef NOT_TESTING //if NOT_TESTING was NOT defined
int main() {
    //main function here
}
#endif

    When you want to compile the main function in foo.c, you simply add the option -DNOT_TESTING to your compile command. If you want to compile the main function in test.c, don't add that option.