'isnan' was not declared in this scope if (isnan(t)) ；这样的问题怎么解决?

[changtj]

H:\vcpkg\downloads\log4z-master\g++>cmake -Dlog4z_SOURCE_DIR=".." -G "MinGW Makefiles" CMake Error: Error: generator : MinGW Makefiles Does not match the generator used previously: Visual Studio 15 2017 Either remove the CMakeCache.txt file and CMakeFiles directory or choose a different binary directory.

H:\vcpkg\downloads\log4z-master\g++>cmake -Dlog4z_SOURCE_DIR=".." -G "MinGW Makefiles" -- The C compiler identification is GNU 5.3.0 -- The CXX compiler identification is GNU 5.3.0 -- Check for working C compiler: C:/Qt/Qt5.9.2/Tools/mingw530_32/bin/gcc.exe -- Check for working C compiler: C:/Qt/Qt5.9.2/Tools/mingw530_32/bin/gcc.exe -- works -- Detecting C compiler ABI info -- Detecting C compiler ABI info - done -- Detecting C compile features -- Detecting C compile features - done -- Check for working CXX compiler: C:/Qt/Qt5.9.2/Tools/mingw530_32/bin/g++.exe -- Check for working CXX compiler: C:/Qt/Qt5.9.2/Tools/mingw530_32/bin/g++.exe -- works -- Detecting CXX compiler ABI info -- Detecting CXX compiler ABI info - done -- Detecting CXX compile features -- Detecting CXX compile features - done -- Configuring done -- Generating done -- Build files have been written to: H:/vcpkg/downloads/log4z-master/g++

H:\vcpkg\downloads\log4z-master\g++>mingw32-make Scanning dependencies of target log4z [ 50%] Building CXX object CMakeFiles/log4z.dir/H_/vcpkg/downloads/log4z-master/log4z.cpp.obj In file included from H:\vcpkg\downloads\log4z-master\log4z.cpp:37:0: H:\vcpkg\downloads\log4z-master\log4z.h: In member function 'zsummer::log4z::Log4zStream& zsummer::log4z::Log4zStream::writeDouble(double, bool)': H:\vcpkg\downloads\log4z-master\log4z.h:810:16: error: 'isnan' was not declared in this scope if (isnan(t)) ^ H:\vcpkg\downloads\log4z-master\log4z.h:810:16: note: suggested alternative: In file included from H:\vcpkg\downloads\log4z-master\log4z.h:193:0, from H:\vcpkg\downloads\log4z-master\log4z.cpp:37: C:/Qt/Qt5.9.2/Tools/mingw530_32/i686-w64-mingw32/include/c++/cmath:862:5: note: 'std::isnan' isnan(_Tp __f) ^ In file included from H:\vcpkg\downloads\log4z-master\log4z.cpp:37:0: H:\vcpkg\downloads\log4z-master\log4z.h:815:21: error: 'isinf' was not declared in this scope else if (isinf(t)) ^ H:\vcpkg\downloads\log4z-master\log4z.h:815:21: note: suggested alternative: In file included from H:\vcpkg\downloads\log4z-master\log4z.h:193:0, from H:\vcpkg\downloads\log4z-master\log4z.cpp:37: C:/Qt/Qt5.9.2/Tools/mingw530_32/i686-w64-mingw32/include/c++/cmath:853:5: note: 'std::isinf' isinf(_Tp __f) ^ H:\vcpkg\downloads\log4z-master\log4z.cpp: In member function 'virtual zsummer::log4z::LogData* zsummer::log4z::LogerManager::makeLogData(LoggerId, int)': H:\vcpkg\downloads\log4z-master\log4z.cpp:1262:38: warning: 'thread' attribute directive ignored [-Wattributes] static __declspec(thread) tm g_tt = { 0 }; ^ H:\vcpkg\downloads\log4z-master\log4z.cpp:1263:42: warning: 'thread' attribute directive ignored [-Wattributes] static declspec(thread) time_t g_curDayTime = 0 ; ^ CMakeFiles\log4z.dir\build.make:61: recipe for target 'CMakeFiles/log4z.dir/H/vcpkg/downloads/log4z-master/log4z.cpp.obj' failed mingw32-make[2]: *** [CMakeFiles/log4z.dir/H/vcpkg/downloads/log4z-master/log4z.cpp.obj] Error 1 CMakeFiles\Makefile2:66: recipe for target 'CMakeFiles/log4z.dir/all' failed mingw32-make[1]: *** [CMakeFiles/log4z.dir/all] Error 2 Makefile:128: recipe for target 'all' failed mingw32-make: *** [all] Error 2

H:\vcpkg\downloads\log4z-master\g++>g++ g++: fatal error: no input files compilation terminated.

H:\vcpkg\downloads\log4z-master\g++>mingw32-make -version GNU Make 4.1 Built for i686-w64-mingw32 Copyright (C) 1988-2014 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later http://gnu.org/licenses/gpl.html This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.

H:\vcpkg\downloads\log4z-master\g++>

[vrqq]

试试在前面加上std:: 变成std::isnan std::isinf

然后打一下__cpluscplus看看是不是这个原因