__PRETTY_FUNCTION__ in Visual C++

Question

While playing around with Visual C++ from Visual Studio 2017 (15.5.6 to be exact) I noticed that __PRETTY_FUNCTION__ from GCC seems to work! - to some degree at least…

It did show up along suggestions while typing:

Also it had its value shown in tooltip as expected:

And yet compiling the code using __PRETTY_FUNCTION__ results in an error:

error C2065: '__PRETTY_FUNCTION__': undeclared identifier

So, is there any way to make it work in Visual C++? Some include perhaps? Or some special compilation settings? (I think I'm using default ones.) Why would it work in shown examples, but not in actual use?!

Note, that I'm not looking for Visual C++ alternatives for __PRETTY_FUNCTION__. I know them already. I'm just surprised and curious about the behavior here.

Nesmith

Remember that Intellisense is a different compiler than what is used to compile your code. – Tao

@Tao Is it? That I didn't knew... Kind of surprising actually! (To me at least...) Where do you know this from? And does it explain this effect or is just a possible reason? – Nesmith

That's interesting. I could understand this happening with some third party IDE like Eclipse etc. But apparently Microsoft's own IDE knows something about __PRETTY_FUNCTION__, even though their compiler doesn't support it? – Karyn

blogs.msdn.microsoft.com/vcblog/2009/05/27/… – Tao

Yeah that's "pretty" funny to be fair – Sometimes

EDG's C++ Front End documentation mentions it on page 71 - "1.13 Predefined Macro" together with Micsosoft's own __FUNCSIG__. – Draggletailed

Answer 1

So, is there any way to make it work in Visual C++? Some include perhaps? Or some special compilation settings? (I think I'm using default ones.) Why would it work in shown examples, but not in actual use?!

No.

The Visual Studio uses the Edison Design Group C++ Front End for the InteliSense, as explained in the Visual C++ Team Blog's Rebuilding Intellisense and here, and not the Microsoft C++ compiler. This means that some of the features available to the Intellisense are not available in compile time.

EDG's C++ Front End documentation mentions that its supports some of the GCC pre-defines like __PRETTY_FUNCTION__ on page 71 - "1.13 Predefined Macros" together with Microsoft's __FUNCSIG__.

You can even see the version of the EDG by typing __EDG_VERSION__ and hovering over it.

Draggletailed

There is a way to make it sort-of work. Include the following: #define __PRETTY_FUNCTION__ __FUNCSIG__ – Annora

full macro check #ifdef _MSC_VER #define __PRETTY_FUNCTION__ __FUNCSIG__ #endif – Multicolored

Pedantic but note that __PRETTY_FUNCTION__ is a reserved identifier, best practice not to #define it – Truett

Answer 2

You can emulate it pretty well by putting this in some common header (for example, your precompiled header, if you're using that):

#if !defined(__PRETTY_FUNCTION__) && !defined(__GNUC__)
#define __PRETTY_FUNCTION__ __FUNCSIG__
#endif

It doesn't evaluate to exactly the same as PRETTY_FUNCTION, but it's a human-readable representation of the function name with argument types.

Segovia

This does not work in gcc/clang. You will get the error: gcc.godbolt.org/z/774vnn5Kr – Taking

For people who just copy-and paste, I improved the solution to be GNU compatible out of the box. – Segovia

It seems that __PRETTY_FUNCTION__ is not a regular macro, and its availability cannot be checked like that with #ifdef or similar. – Sanguineous

@LauriNurmi It can not be a macro because the preprocessor does not understand what a function it. Both C and C++ specify __func__ as a magic identifier and so are all extensions/alternatives of it. – Denbrook