Olaf van der Spek

Is it OK if Abseil is build with 11 and the program itself is build with 17?

It's actually related to https://github.com/abseil/abseil-cpp/issues/260 If it's a bad idea and the compiler defaults to C++14 (GCC 6) and Abseil defaults to C++11 then something is wrong.

`set(CMAKE_CXX_FLAGS -std=c++17)` which is wrong. ;) But what if c++17 became the default in a future GCC, like c++14 already is? `CMAKE_CXX_STANDARD` might not be set in that case.

> We don't set CMAKE_CXX_STANDARD, we only read it. That might not be right. If it's unset, you default to C++11 which might not be what the compiler defaults to.

> so even if they use a compiler that doesn't default to c++11 or later (gcc4.9) IIRC the default has never been C++11. GCC 6 defaults to C++14, before that...

But if myexec sets it directly it trickles down to abseil, isn't that a bit weird?

Sounds like a design bug in cmake..

If modes can't be mixed you should have separate library builds for each mode.. like you have separate builds for amd64 and arm and x86. Or you shouldn't have libraries...

> What do we think if this idea -- provide a flag -DABSL_NO_DEFAULT_STD_VALUE for people to try to make sure their code builds, This will result in very limited testing..

> I did some experimenting, with compilers which default both to c++98 and to c++14. It seems that for pretty much all cases using a private requirement should work for...