Showing posts from January, 2021

OpenCV and CUDA - updated build notes

Yes, this comes up a lot, and if you're getting mysterious build breaks, maybe it's a mismatch between what version of gcc/g++ CUDA requires, your default compiler. The symptoms are that cmake completes just fine (so it found a compiler, all the libraries, etc) but then you get a "failed to compile" error when you do a "make -j[number]" The first thing to do is to run a single-instance make, because the errors will likely be less obtuse.  When I did this, I got: "error: #error -- unsupported GNU version! gcc versions later than 8 are not supported! " gcc --version told me it was version 9, so there's the problem.  But how to get around it? Make sure you have a suitable version of gcc and g++ installed (version 8) in our case.  On Ubuntu, you can do this with: "sudo apt install -y gcc-8 g++-8" Tell cmake about it when you do the pre-build with: "-D CMAKE_C_COMPILER=gcc-8 -D CMAKE_CXX_COMPILER=g++-8" To wrap up, the cmake comm