How to work around CMake + XCode 4 paths dependencies? - c++

Question

I have projects structured like so:
Libs/
Apps1/
Apps2/
In each folder is a CMakeLists.txt. I would like to generate a project file for each of the folders, and each AppsN references Libs. My method of doing that is by calling CMake's add_subdirectory(../Libs/Source/LibN) etc.
Now when I do this, CMake says add_subdirectory must specify a unique absolute path for the binary output folder.
See this post:
Xcode dependencies across different build directories?
XCode can not handle dependencies when the build output folder is unique per target. It needs one folder. And CMake does this by default, it just refuses to when the folder is not a subdir.
I tried altering and changing the output path after the target is created. This will build the objects to the output folder, XCode sees them, but all references to this target in the CMake script will use the unique path.
Proposed solutions are:
include project files in App1/Projects/Subdir and duplicate projects in an irrelevant location
reorganize my folders to a shared parent folder to avoid this CMake craziness, which presents some security problems for me (as some dirs are not public)
never refer to the target by its CMake name, instead using the shared path name. Not sure how to do this properly
try and get this patched on the CMake side somehow
switch to premake

Answer 1

Try to add the following to the root CMakeLists.txt:
CMAKE_MINIMUM_REQUIRED(VERSION 2.8.0)
PROJECT (ContainerProject)
SET (LIBRARY_OUTPUT_PATH ${ContainerProject_BINARY_DIR}/bin CACHE PATH
"Single output directory for building all libraries.")
SET (EXECUTABLE_OUTPUT_PATH ${ContainerProject_BINARY_DIR}/bin CACHE PATH
"Single output directory for building all executables.")
MARK_AS_ADVANCED(LIBRARY_OUTPUT_PATH EXECUTABLE_OUTPUT_PATH)
# for common headers (all project could include them, off topic)
INCLUDE_DIRECTORIES(ContainerProject_SOURCE_DIR/include)
# for add_subdirectory:
# 1) do not use relative paths (just as an addition to absolute path),
# 2) include your stuffs in build order, so your path structure should
# depend on build order,
# 3) you could use all variables what are already loaded in previous
# add_subdirectory commands.
#
# - inside here you should make CMakeLists.txt for all libs and for the
# container folders, too.
add_subdirectory(Libs)
# you could use Libs inside Apps, because they have been in this point of
# the script
add_subdirectory(Apps1)
add_subdirectory(Apps2)
In Libs CMakeLists.txt:
add_subdirectory(Source)
In Source CMakeLists.txt:
add_subdirectory(Lib1)
# Lib2 could depend on Lib1
add_subdirectory(Lib2)
In this way all Apps could use all libraries. All binary will be made to your binary ${root}/bin.
An example lib:
PROJECT(ExampleLib)
INCLUDE_DIRECTORIES(
${CMAKE_CURRENT_BINARY_DIR}
${CMAKE_CURRENT_SOURCE_DIR}
)
SET(ExampleLibSrcs
...
)
ADD_LIBRARY(ExampleLib SHARED ${ExampleLibSrcs})
An example executable (with dependency):
PROJECT(ExampleBin)
INCLUDE_DIRECTORIES(
${CMAKE_CURRENT_BINARY_DIR}
${CMAKE_CURRENT_SOURCE_DIR}
${ExampleLib_SOURCE_DIR}
)
SET(ExampleBinSrcs
...
)
# OSX gui style executable (Finder could use it)
ADD_EXECUTABLE(ExampleBin MACOSX_BUNDLE ${ExampleBinSrcs})
TARGET_LINK_LIBRARIES(ExampleBin
ExampleLib
)
Here is a stupid and working example.