错误<ratio>和<memory>从vs2013升级到vs2017后

Question

I recently upgraded to Visual Studio 2017 and now I get a syntax error in from standard library.

This is the output:

C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\VC\Tools\MSVC\14.11.25503\include\ratio(220): error C2947: expecting '>' to terminate template-argument-list, found '<' 
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\VC\Tools\MSVC\14.11.25503\include\ratio(221): error C2226: syntax error: unexpected type 'std::integral_constant<_Ty,_Val>::type' 
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\VC\Tools\MSVC\14.11.25503\include\ratio(221): error C2988: unrecognizable template declaration/definition
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\VC\Tools\MSVC\14.11.25503\include\ratio(221): error C2059: syntax error: ',' 

This is where it happens:

template<class _R1,
    class _R2,
    bool _Sfinae>
    struct _Ratio_multiply_sfinae<_R1, _R2, _Sfinae, void_t<
        typename _Ratio_multiply<_R1, _R2>::_Num::type,
        typename _Ratio_multiply<_R1, _R2>::_Den::type>>
    {   // typename ratio<>::type is unnecessary here
    typedef ratio<
        _Ratio_multiply<_R1, _R2>::_Num::value,
        _Ratio_multiply<_R1, _R2>::_Den::value> type;
    };

My guess is that somehow the compiler thinks >> is an operator, but I can't edit it to > > for testing purposes.

I haven't included <ratio> but I think it is used for <chrono> and therefore <mutex> .

Update:

I just realized that during compilation, InteliSense complains about that place, but before and after compiling it doesn't complain about it. Somehow it seems the compiler setting have been changed, but how I don't know. The other question is why did it work with vs2013.

Answer 1

I think the standard changed between C++03 and C++11 to address the issue you mentioned about "> >" vs ">>"

You might need to switch compiler versions.

Answer 2

This is an old topic. But I recently faced a very similar issue. The root cause was that somewhere in the code there was a define like

#define void_t void

which provoked the compiler errors. Turning it to typedef helped.

As you can see void_t is used in the definition of _Ratio_multiply_sfinae and is also defined in the <ratio> as a templated structure. The define above messed up everything.