homebrew gcc/c++ problem Mac

By swylieUncategorized

Incase anyone has this problem when installing SID:

When installing SID

When I ran the command:

cmake -DCMAKE_C_COMPILER=/opt/local/bin/gcc -DCMAKE_CXX_COMPILER=/opt/local/bin/c++ ..

I got the error:

CXX_COMPILER=/opt/local/bin/c++ ..

— The C compiler identification is unknown

— The CXX compiler identification is unknown

CMake Error at CMakeLists.txt:5 (PROJECT):

  The CMAKE_C_COMPILER:

    /opt/local/bin/gcc

  is not a full path to an existing compiler tool.

 

 

I fixed it by changing the original command to:

cmake -DCMAKE_C_COMPILER=/usr/local/bin/gcc-8 -DCMAKE_CXX_COMPILER=/usr/local/bin/c++-8 ..

Homebrew installed gcc and c++ in the usr folder and gave them the names gcc-8, c++-8

2 thoughts on “homebrew gcc/c++ problem Mac”

  1. As one needs to have the “standard” gcc and g++ commands on the path (being listed before those in /usr/bin !) , as a temporary fix we made two logical links in /usr/local/bin:

    sudo ln -s gcc-8 gcc
    sudo ln -s c++-8 c++

    This was the definitive solution!
    This should be have done automatically on gcc installation, I believe, but there must be something wrong on High Sierra OS. See e.g. this page:
    https://stackoverflow.com/questions/48175913/homebrew-wont-link-gcc-on-mac-high-sierra

    After a manual clean in the “contrib” directory (this will be fixed in the next SID version):

    cd ../contrib
    make clean

    redo the cmake command using the logical links:

    cd ../Build
    make clean
    cmake -DCMAKE_C_COMPILER=/usr/local/bin/gcc -DCMAKE_CXX_COMPILER=/usr/local/bin/c++ ..

    and then make, make install:

    make
    sudo make install

    All working!

    L.

  2. In my case, we had to do also this link
    sudo ln -s g++-8 g++
    after making
    sudo ln -s gcc-8 gcc
    sudo ln -s c++-8 c++
    Now everything works! YAY!
    Best wishes,
    C.

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