cmake, add_custom_command with dependencies from a different directory

cmake

Solution

CMake docs for `add_custom_target`:

By default nothing depends on the custom target. Use ADD_DEPENDENCIES to add dependencies to or from other targets.

So I suggest to "connect" the targets with

ADD_DEPENDENCIES( full_out part_out )

EDIT: Working example

As it turned out, you need to set the source file properties for `part.out`

Here is my working example (tried under Windows with VS2008):

CMakeLists.txt:

cmake_minimum_required(VERSION 2.8 )
project( full )

add_subdirectory( details )

add_custom_command( OUTPUT full.out 
               COMMAND ${CMAKE_COMMAND} -E copy ./details/part.out full.out
               DEPENDS details/part.out 
               )


add_custom_target( full_out
               DEPENDS full.out details/part.out details/part.src
              )


set_source_files_properties( details/part.out PROPERTIES GENERATED TRUE ) 


add_dependencies( full_out part_out )

details/CMakeLists.txt:

cmake_minimum_required(VERSION 2.8 )
project(part)

add_custom_command(OUTPUT part.out
               COMMAND ${CMAKE_COMMAND} -E copy ${CMAKE_CURRENT_SOURCE_DIR}/part.src part.out
               DEPENDS part.src)

add_custom_target(part_out
              DEPENDS part.out)

This example worked for all of your 3 stated cases.

Problem

I have a question about CMake which seems to be commonly asked here, but none of the answers seem to solve my problem. In the `details` subdirectory, there is a `CMakeLists.txt` which contains: ``` add_custom_command(OUTPUT part.out COMMAND foo --input=part.src --output=part.out DEPENDS part.src) add_custom_target(part_out DEPENDS part.out) ``` In the main directory there is a `CMakeLists.txt` which uses `part.out` for generating another file: ``` add_custom_command(OUTPUT full.out COMMAND bar --input=./details/part.out --output=full.out) add_custom_target(full_out DEPENDS full.out) ``` The problem is that I want 3 things to happen here: - if `part.out` doesn't exist it needs to be generated - if `part.out` is out of date (`part.src` is newer than `part.out`) I want it to be regenerated - if `full.out` is out of date (`part.out` is newer than `full.out`, or `full.out` desn't exist) I want it to be (re)generated So if I add `DEPENDS ./details/part.out` to `add_custom_command(OUTPUT full.out)` I will achieve points 2 and 3, but not point 1, because if I delete `part.out` and then I call `make full_out` I'll get an error that there is no rule to make `./details/part.out` (as it is a rule from another directory). If I add `DEPENDS full_out` to `add_custom_command(OUTPUT full.out)` or to `add_custom_target(full_out)` I'll achieve points 1 and 2, but not 3, because even if `part.out` was regenerated, a `full.out` will not be regenerated, as it doesn't depend on the `part.out` file itself. So how can I connect both scenarios? I was thinking about adding both `DEPENDS` but how do I know if that will always work? I mean in such case the order of build will matter here.

Original source