C++ macro to get full function path and declaration

Question

I want to get full function path and declaration in code via macro or some compiler magic. I have this code (click here to run):

#include <iostream>

namespace NS {

    struct Foo {
        static int sum(int a, int b) {
            std::cout << "This is from " << __FILE__ << ":" << __LINE__ << " @ " <<     __func__ << std::endl;
            return a+b;
        }

        static int sum(int a, int b, int c) {
            std::cout << "This is from " << __FILE__ << ":" << __LINE__ << " @ " <<     __func__ << std::endl;
            return a+b+c;
        }

   };
}

int main() {
    NS::Foo::sum(1,2);
    NS::Foo::sum(1,2, 3);
}

And I get the output:

This is from /some/where/main.cpp:7 @ sum
This is from /some/where/main.cpp:12 @ sum

My questions are:

How do I get the full path of sum function invoked?(NS::Foo::sum)
How can I get the full function declaration with argument types?( sum(int, int) or sum(int, int, int))

I am interested in mainstream compilers: Clang, GCC, Microsoft C++ compiler

@Olaf, thanks for edit. I understand it, it's just a bad habit. — lukas.pukenis, Jan 11 '16 at 09:20
There is a reason macros are processed by the **pre**processor. They are textual replacements and have no idea about the "normal" C++ code (btw. **this* is the same for all pre-processors). — too honest for this site, Jan 11 '16 at 09:20
Are you trying to detect the full path where the file is located in? — sameera sy, Jan 11 '16 at 09:22
What do you mean by the "full path of sum function"? Functions don't have paths. Do you mean the fully qualified name ("NS::Foo::sum")? (If you do, see [this question](http://stackoverflow.com/questions/4384765/whats-the-difference-between-pretty-function-function-func)). — molbdnilo, Jan 11 '16 at 09:23
@sameerasy: I understand the question that OP wants to show where the _method_ is invoked. — too honest for this site, Jan 11 '16 at 09:24
@Olaf : C++ is not Java is not C++, `sum` is a _member function_. ;-D — ildjarn, Jan 11 '16 at 09:25
@ildjarn: https://en.wikipedia.org/wiki/Method_(computer_programming). There's more than C++ and Java! — too honest for this site, Jan 11 '16 at 09:26
@Olaf : The smiley implied the joke, but if you want to be pedantic, the C++ standard has no notion or definition of the term 'method'. And you made the point that we're discussing C++, after all. ;-] — ildjarn, Jan 11 '16 at 09:27
You missed the point. _method_ is the standard term. The C++ standard does also not define some other common terms. Yet they do apply. But thanks for providing the correct term. I prefer C and Python. — too honest for this site, Jan 11 '16 at 09:29
@Olaf : And you're still missing the point that it was a joke. — ildjarn, Jan 11 '16 at 09:31
@lukas.pukenis : Also of note here, although not immediately usable that I'm aware of, is [N4519](http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4519.pdf)'s proposed `std::experimental::source_location`, which is part of the Library Fundamentals v2 TS. — ildjarn, Jan 11 '16 at 09:35
Notice that C++11 has anonymous functions (e.g. *lambda*s).... You probably won't be able to get something fancy in that case — Basile Starynkevitch, Jan 11 '16 at 09:49

score 3 · Answer 1 · answered Jan 11 '16 at 09:26

3

Answering for GCC.

Checkout the __PRETTY_FUNCTION__ macro. I've found it in the defintion of assert macro in <assert.h>. Perhaps same could be found for other compilers and libc implementations.

answered Jan 11 '16 at 09:26

Oleg Andriyanov

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Nice! It's even supported in Clang. Thanks – lukas.pukenis Jan 11 '16 at 09:28

Zereges · Answer 2 · 2016-01-11T09:33:47.607

3

For Microsoft Visual Studio compiler, __FUNCSIG__ can give you a lot about the function.

__FUNCSIG__ will give you full function signature
__FUNCDNAME__ gives magnled name.
__FUNCTION__ is just for function name.

edited Jan 11 '16 at 09:33

answered Jan 11 '16 at 09:30

Zereges

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Seems to be what I needed for visual studio. Thank you – lukas.pukenis Jan 11 '16 at 09:31

score 2 · Answer 3 · edited Jan 12 '16 at 21:23

If you don't want to limit yourself to a single compiler, and don't fancy writing a pre-processor ifdef chain yourself, boost has already defined a macro BOOST_CURRENT_FUNCTION which is defined as the full function signature macro that's defined on the used compiler. __PRETTY_FUNCTION__ in gcc and other compilers that support that, __FUNCSIG__ where that is supported (msvc), also supports some lesser used compilers and falls back to __func__ as defined by the C standard (or a static placeholder if even that's not supported).

C++ macro to get full function path and declaration

3 Answers3