Why am I getting this error with MinGW and Cmake? - c++

Question

So I am trying to compile this flip fluids addon with blender, so I followed this tutorial, https://www.youtube.com/watch?v=TVKM1egDoGs , So I first ran cmake.exe -G "MinGW Makefiles" .. and it was telling me that it was missing a CMakeLists File... So I added one... then I ran cmake.exe --build . and it got to 3 percent than showed me errors like ...
In file included from C:/Users/N/Downloads/Blender-FLIP-Fluids-master/src/engine/threadutils.h:29,
from C:/Users/N/Downloads/Blender-FLIP-Fluids-master/src/engine/meshlevelset.h:65,
from C:/Users/N/Downloads/Blender-FLIP-Fluids-master/src/engine/meshobject.h:30,
from C:/Users/N/Downloads/Blender-FLIP-Fluids-master/src/engine/fluidsimulation.h:38,
from C:\Users\N\Downloads\Blender-FLIP-Fluids-master\src\engine\c_bindings\fluidsimulation_c.cpp:25:
C:/PROGRA~2/MINGW-~1/I686-8~1.0-P/mingw32/lib/gcc/i686-w64-mingw32/8.1.0/include/c++/mutex:93:9: note: previous definition of 'class std::recursive_mutex'
class recursive_mutex : private __recursive_mutex_base
^~~~~~~~~~~~~~~
In file included from C:/Users/N/Downloads/Blender-FLIP-Fluids-master/src/engine/mingw32_threads/mingw.condition_variable.h:25,
from C:/Users/N/Downloads/Blender-FLIP-Fluids-master/src/engine/threadutils.h:31,
from C:/Users/N/Downloads/Blender-FLIP-Fluids-master/src/engine/meshlevelset.h:65,
from C:/Users/N/Downloads/Blender-FLIP-Fluids-master/src/engine/meshobject.h:30,
from C:/Users/N/Downloads/Blender-FLIP-Fluids-master/src/engine/fluidsimulation.h:38,
from C:\Users\N\Downloads\Blender-FLIP-Fluids-master\src\engine\c_bindings\fluidsimulation_c.cpp:25:
C:/Users/N/Downloads/Blender-FLIP-Fluids-master/src/engine/mingw32_threads/mingw.mutex.h:142:44: error: conflicting declaration 'typedef class std::_NonRecursive<std::recursive_mutex> std::mutex'
This is the full error https://pastebin.com/KTnALG1E, where is this coming from?? is it a mingw error or what? Can someone help please?

Answer 1

Your full error message includes a more interesting bit:
C:/Users/N/Downloads/Blender-FLIP-Fluids-master/src/engine/mingw32_threads/mingw.thread.h:32:2:
error: #error This version of MinGW seems to include a win32 port of
pthreads, and probably already has C++11 std threading classes
implemented, based on pthreads. It is likely that you will get class
redefinition errors below, and unfortunately this implementation can
not be used standalone and independent of the system header,
since it relies on it for std::unique_lock and other utility classes.
If you would still like to use this implementation (as it is more
lightweight), you have to edit the c++-config.h system header of your
MinGW to not define _GLIBCXX_HAS_GTHREADS. This will prevent system
headers from defining actual threading classes while still defining
the necessary utility classes.
So either install a different version of mingw or edit your mingw files according to the instructions above.