Support for __VA_OPT__ in gcc

[Jonathan Wakely]

On Tue, 1 Oct 2019 at 01:25, Edward Diener wrote:
> How do I find out, for a given gcc compiler product such as gcc-9.2,
> what the gnu extensions are when I specify '-std=c++nn' and when I
> specify '-std=gnu++nn' for any given valid 'nn' ? When I look in the
> documentation for '-std' in gcc-9.2 the only explanation I can see at
> https://gcc.gnu.org/onlinedocs/gcc-9.2.0/gcc/C-Dialect-Options.html#C-Dialect-Options
> does not give me that information. Does it exist somewhere online or in
> the gcc docs ?

The documented extensions (and when they are enabled) are covered in
https://gcc.gnu.org/onlinedocs/gcc-9.2.0/gcc/#toc-Extensions-to-the-C-Language-Family
and https://gcc.gnu.org/onlinedocs/gcc-9.2.0/gcc/#toc-Extensions-to-the-C_002b_002b-Language
(or just search for "extensions" in the TOC).