Is __COUNTER__ macro portable?

Question

I have a piece of code which uses __COUNTER__ macro to generate unique names for variables.

Is this code portable ? I know that GCC and MSVS support it.

Answer 1

It seems NO. When I ctrl+f "__COUNTER__" on standard pdf, I couldn't find anything >o<

Answer 2

It's definitely not standard.

It's a compiler extension (GNU C extensions)

The common predefined macros are GNU C extensions.

and a Microsoft-specific one,

Microsoft-Specific Predefined Macros:

__ COUNTER __

also supported by clang as language extension.

The standard doesn't mention it anywhere.

Answer 3

GCC manual, section Common Predefined Macros, states

The common predefined macros are GNU C extensions.

I've also never seen this macro in the C99, C11 or C++11 standards.

As for practical portability: Clang supports it, too.