How to add code at the entry of every function?

Question

I want to add some code before every function call to do some checking. The only way I know is:

#define SOME_CODE printf(\"doing something...\");

class test         


        

Answer 1

For gcc there's a similar solution to the MSVC one someone else posted as an answer:

#include 
int depth=-1;
extern "C" {
    void __cyg_profile_func_enter (void *, void *) __attribute__((no_instrument_function));
    void __cyg_profile_func_exit (void *, void *) __attribute__((no_instrument_function));
    void __cyg_profile_func_enter (void *func,  void *caller)
    {
        depth++;
    }


    void __cyg_profile_func_exit (void *func, void *caller)
    {
        depth--;
    }
}

class Foo {
public:
    void bar() {
        std::cout << "bar: " << depth << std::endl;
    }
};

int main() {
    Foo f;
    f.bar();
    return 0;
}

Compile with g++ -Wall -Wextra -finstrument-functions. Be careful not to call an instrumented function from within the instrument hooks though! (See the man page for ways of excluding things)