__PRETTY_FUNCTION__ definition issue

[landwehrj]

The check for PRETTY_FUNCTION at least on gcc returns false in the g3log/g3log.hpp:33:

#if !(defined(__PRETTY_FUNCTION__))

For instance, I tested the following code:

#if defined(__PRETTY_FUNCTION__)
error
#endif 

#include <iostream>

int main() {
  std::cout << __PRETTY_FUNCTION__ << std::endl;
  return 0; 
}

Which compiles and runs fine. I assume it's because the PRETTY_FUNCTION is a magic literal and not a macro?

This causes issues with other libraries that use the literal when including g3log.hpp because g3log.hpp overrides the magic literal.

[KjellKod]

https://gcc.gnu.org/onlinedocs/gcc/Function-Names.html

PRETTY_FUNCTION should be AFAIK part of gcc, potentially depending on GCC setup that is not the case for you. I think there are potentially bigger problems lurking for you , when gcc is compiling one library in one way and you are integrating other libraries that are constructed with a whole different GCC setup. At least that's how I interpret your answer.

I don't see this as an issue with g3log . This seems to be to be a system setup issue on your company's side.

g3log is public domain, so one option is to fork the repo and remove the troublesome code - if you can't align the GCC configurations across your systems.

[landwehrj]

I think there may be some misunderstanding. So what I am trying to convey is that it is part of gcc, but is not defined as a macro. It's a magic literal. It doesn't get defined until compile time after the preprocessor AFAIK. You can't test it with defined(), I believe.

So what's happening with g3log is that it is always overriding the built-in PRETTY_FUNCTION literal as far as I can tell.

Here is an example that shows it not being defined but printing the result:
https://coliru.stacked-crooked.com/a/93197612dbae85cc

You can click edit and recompile it if you want.

Here's a stack overflow post that confirms my thoughts:
https://stackoverflow.com/a/48223048/15387245

[KjellKod]

Look at that. "Magic Constants" -- and I considered myself a (at one time at least) C++ expert. You learn something new everyday.

It seems that the idef check is just nonsense in this case. Since we really want the adorned function, through __PRETTY_FUNCTION__, maybe just remove that ifdef definition section from the code?

Please put up a PR so we can evaluate. Nice find!

ref: https://gcc.gnu.org/onlinedocs/gcc/Function-Names.html