Are Variadic macros nonstandard?

Question

For debugbuilds, I usually use Clang, as it formats warnings and errors better, and makes it a little easier to track them down, and fix them.

But recently after add

Answer 1

Quote Wikipedia:

Variable-argument macros were introduced in 1999 in the ISO/IEC 9899:1999 (C99) revision of the C language standard, and in 2011 in ISO/IEC 14882:2011 (C++11) revision of the C++ language standard.

So it's standard from C99 and C++11 onwards, but a GNU extension in C++03.