C++ macro to log every line of code

Question

During one of my recent discussions with my manager, he mentioned that one of his former clients used a C++ macro to log info about every line of code. All they had to do was en

Answer 1

I don't know if every line/variable can be expanded like that, but function calls can be logged. I have logged all function calls using the -finstrument-functions option of gcc. It will call:

  void __cyg_profile_func_enter (void *this_fn, void *call_site);

and

   void __cyg_profile_func_exit  (void *this_fn, void *call_site);

for function enter and exit.

The docs explain how to use it. I don't know if other compilers offer something similar.

Answer 2

You may check how BOOST_CHECKA from Boost.Test is implemented. Internally it uses expression templates.

For test:

#define BOOST_TEST_MAIN

#include <boost/test/included/unit_test.hpp>
#include <boost/test/test_tools.hpp>

BOOST_AUTO_TEST_CASE(test1)
{
    int a=0;
    int b=1;
    int c=2;
    BOOST_CHECKA( a+b == c );
}

Output is:

Running 1 test case...
main.cpp(11): error: in "test1": check a+b == c failed [0+1!=2]

*** 1 failure detected in test suite "Master Test Suite"

Note values in square brackets: [0+1!=2]

It has some limitations.

For test:

BOOST_CHECKA( (a+b) == c );

output is:

check (a+b) == c failed [1!=2]