[CMake] static library from several subdirectories

[Verweij, Arjen]

Hi,

>From: Michael Wild [mailto:themiwi at gmail.com]

>>> You have to call ADD_SOURCES for all your sources BEFORE you do the
>>> ADD_LIBRARY call.
>>
>> I am already doing this, but since the files I was adding to the
>library didn't exist, the call failed. I somehow expected cmake to start
>executing the custom command since there was a previously defined
>dependency, but apparently cmake wasn't set up for the way I'm
>mistreating it :)
>>
>> What triggers a custom command to be executed? With your help I have
>arrived at:
>
>
>You should add a "DEPENDS <input_file1> <input_file2> ..." option to
>your ADD_CUSTOM_COMMAND calls, then CMake will know when to invoke it,
>otherwise it can't know anything about the dependency.

Alright. I have spent a considerable amount of time experimenting, rewriting and testing. I have reduced my problem to hello world inside a hello.cr file. add_sources() has been molested and reduced to a mere shadow of its former glory. With or without DEPENDS doesn't change matters, although I'm sure without is bad form. Layout:

CMakeLists.txt (code below)
h -- CMakeLists.txt (it just calls add_sources() -- without any arguments)
| -- hello.cr (your typical hello world)

So, when I call add_sources() directly from the top level CMakeLists.txt file, I obtain my executable "test". If I comment out the add_sources() call, and use add_subdirectory(h) instead, and call add_sources() from there, it fails. The complaint is that it cannot find source file "hello.c" Apparently the problem is that add_custom_command() calls are local to the directory they are called in, and since the executable is assembled from a list on a higher level, it expects to find the source file on disc already :(

PROJECT(Test)
enable_language( C )
cmake_minimum_required(VERSION 2.8)

function (add_sources)
    define_property(GLOBAL PROPERTY list BRIEF_DOCS "brief" FULL_DOCS "full")

    SET ( out_file "/mnt/usr3/people/verweija/cmake2/build/h/hello.c" )
    SET ( in_file "/mnt/usr3/people/verweija/cmake2/h/hello.cr" )

    ADD_CUSTOM_COMMAND(
        OUTPUT ${out_file}
        COMMAND ${CMAKE_COMMAND} -E copy ${in_file} ${out_file}
        DEPENDS "/mnt/usr3/people/verweija/cmake2/h/hello.cr"
        )

    LIST( APPEND mylist ${out_file}  )

    set_property(GLOBAL APPEND PROPERTY "list" "${mylist}")
endfunction(add_sources)

add_sources()
#add_subdirectory( h )

get_property(list GLOBAL PROPERTY list)
message ( STATUS list=${list} )
ADD_EXECUTABLE( "test" ${list} )

I have found some threads about this, and I will be reading them shortly :)

Regards,
Arjen