D:/software/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/../../../../x86_64-w64-mingw32/lib/../lib/libmingw32.a(lib64

This error message indicates that the linker (ld) was unable to find a definition for the WinMain function, which is typically the entry point for Windows GUI applications. This could be due to a missing or improperly defined WinMain function in your code, or a problem with your build environment or linker settings.