CMake cannot find source file (add_executable)

Question

I have been trying to follow the vendor\'s tutorial here: CMake-Tutorial, look over the documentation here: Cmake-Documentation, and educate myself as best as possible with

Answer 1

In add_executable() call relative paths are always interpreted relative to variables CMAKE_CURRENT_SOURCE_DIR or CMAKE_CURRENT_BINARY_DIR.

If you have source files in subdirectories of these dirs, you should explicitely specify these subdirectories:

add_executable(main src/main.cpp)

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Also, variables like PROJECT_SOURCE_DIR should be treated as readonly: while changing them isn't detected by CMake as an error, it breaks some things.

Answer 2

There are some points I'd like to mention.

1. include_directories helps for finding header files. Source files must always have a complete relative path.

   Assuming that your main.cpp is within src, the correct syntax is

   add_executable(main ${PROJECT_SOURCE_DIR}/main.cpp)
   

2. Including ${PROJECT_BINARY_DIR} does not make sense.

3. Overwriting CMake default variables like ${PROJECT_SOURCE_DIR} is no good practice. In future you will always remember that you have done such a thing and for another programmer it is quite unexpected.

Hope it helps.