Running a bash command via CMake

Question

I\'m trying to have CMake either run three bash commands or a bash script. However, I can\'t seem to get it to work.

The bash commands are:

    cd $         


        

Answer 1

execute_process() is executed during configure time. But you want this to run at build time, thus add_custom_command() and add_custom_target() is what you're looking for.

In this special case you want to generate an output file, so you should go for add_custom_command() (both are essentially the same, but command produces one or multiple output files, while target does not.

The cmake snippet for this should look something like the following:

add_custom_command(
    OUTPUT ${CMAKE_SOURCE_DIR}/dependencies/library/lib.o
    WORKING_DIR ${CMAKE_SOURCE_DIR}/dependencies/library
    COMMAND make
)

You then have to add the output file in another target as dependency, and everything should (hopefully) work as expected.

You can also add DEPENDS statements to the add_custom_command() call to rebuild the object file in case some input sources have changed.