CMake subproject cant find compiler

Question

I have a project with a structure as follows:

project
├── build
├── CMakeLists.txt
├── extern (git submodule)
│   └── mylib
│       ├── build
│       ├── CMakeLists.txt
│       └── src
└── src
    └── main.c

mylib has its own build system and it's a git submodule. I want to be able to run cmake --build build in the top level project directory to build the file in project/src, build mylib and then link mylib to the binary built in project.

I use add_subdirectory(extern/mylib) to allow cmake to see and attempt to build the files in extern/mylib. However this does not work and I get the error:

CMake Error at extern/mylib/CMakeLists.txt:4 (project):
  The CMAKE_C_COMPILER:

    riscv64-unknown-elf-gcc

  is not a full path and was not found in the PATH.

riscv64-unknown-elf-gcc is definitely in my PATH as shown by successfully running riscv64-unknown-elf-gcc in the terminal and verifying that the directory shown by which riscv64-unknown-elf-gcc is inside my $PATH variable.

$ which riscv64-unknown-elf-gcc
/opt/riscv/bin/riscv64-unknown-elf-gcc

Is my approach wrong? How should I include this git submodule which my project is dependent on?

The same error is present for CMAKE_CXX_COMPILER.

`riscv64-unknown-elf-gcc` is definitely not a default compiler selected by CMake. How do you specify that compiler? It smells like you have specified it by setting `CMAKE_C_COMPILER` variable in the top-level `CMakeLists.txt` after the `project()` call... — Tsyvarev, Jul 07 '23 at 12:52
Yes, this is wrong: https://stackoverflow.com/a/63944545/3440745. — Tsyvarev, Jul 07 '23 at 12:54
You should be using a [cmake-toolchain](https://cmake.org/cmake/help/latest/manual/cmake-toolchains.7.html) file in that case — Botje, Jul 07 '23 at 12:58

score 0 · Answer 1 · answered Jul 07 '23 at 12:57

0

As pointed out by Tsyvarev, I had incorrectly set CMAKE_C_COMPILER after the project() call in my CMakeLists.txt

answered Jul 07 '23 at 12:57

confusedandsad

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CMake subproject cant find compiler

1 Answers1