GCC minimum version required

[raoulh]

Actually uvw requires a C++14 compiler. Problem is C++14 have a lots of features and not all compiler have all C++14 features working. I tried to build my project using uvw on a Debian Jessie where the current GCC is 4.9.2.

I have a c++14 detection macro in my autotools to detect C++14 availability from the compiler and GCC4.9.2 say it can do C++14.
But I have an error in the build:

uvw/src/uvw/fs.hpp:190:45: error: cannot convert 'std::remove_reference<uv_stat_t&>::type {aka uv_stat_t}' to 'uint64_t {aka long unsigned int}' in initialization
         : path{_path}, stat{std::move(_stat)}

My question here is: Is there a minimum required GCC version that we can check on, or is it worth trying to workaround compilation issue like this one above? or maybe do you know if some checks can be done to detect if compiler can handle this code or not?

[skypjack]

We can use try_compile to test the compiler while running cmake, so that the compilation process is stopped in the early stages. Anyway it sounds like we need to test more or less all the available features from C++14, it isn't that easy to do that.
Moreover, I don't get the error. It has the same type for the data member and for the parameter. Why stat is seen as a long unsigned int? It doesn't make much sense.
Am I missing something?

[raoulh]

I have no idea why stat is long unsigned int... But because it's gcc 4.9.2 it is most likely a compiler bug here.

Of course with a newer GCC (5.3) I don't get any error.

[skypjack]

I see. What I mean is that I wouldn't even know what's the feature to be tested to catch this kind of errors.
Anyway, according with C++ standard support in GCC, I'd definitely say that 4.9 doesn't support C++14.
Therefore, saying that one must use a C++14 fully compliant compiler sounds still good.

[raoulh]

Damn, that's true. And the autoconf macro that checks for -std=gnu++14 tells that gcc4.9 can do C++14...
That's bad.