How to link executable with object created in another CMakeLists.txt in the same project?

Usage
1

My project builds multiple programs in different directories. E.g. suppose the project includes source files in src/progA and src/progB, and there is a CMakeLists.txt file in each of those directories. Further suppose that progB should be linked with an object file corresponding to progA_module.c that’s generated while building progA. How do I portably specify the location of progA_module.c.o in progB/CMakeLists.txt? Something like this, where “CMAKE_SOMETHING_SOMETHING” is actually a standard cmake variable or generator expression?

# Link progB with an object generated for the progA target
set(PROGA_OBJ ${CMAKE_SOMETHING_SOMETHING}/progA_module.c.o)

add_executable(progB
               ${PROGA_OBJ}
               <other stuff here…>)

On my ubuntu system I see that the generated progA_module.c.o is in build/src/progA/CMakeFiles/progA.dir/progA_module.c.o - but I suspect it’s a bad idea to hard-code this path in progB/CMakeLists.txt. How should this location be specified in a portable way?

2

It seems like you want an OBJECT library. With those, their objects are included in any target using them (directly) via target_link_libraries.

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