Can cmake variables be set using add_subdirectory?
I am currently using add_subdirectory(${CMAKE_SOURCE_DIR}/ext/glfw)
to add glfw to my project.
The problem is when I do cmake .. && make it always build all examples and I don't want that to happen.
The cmake file from glfw has
option(GLFW_BUILD_EXAMPLES "Build the GLFW example programs" ON)
Can I set this variable in OFF
from my CMakeLists.txt?
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Just do either
set(GLFW_BUILD_EXAMPLES OFF CACHE BOOL "Build the GLFW example programs")
before the command add_subdirectory
or
cmake -DGLFW_BUILD_EXAMPLES:BOOL=OFF ..
on the command line
For example, for two CMake scripts
cmake_minimum_required(VERSION 2.8)
project(test)
set(OVERRIDE FALSE CACHE BOOL "")
if(OVERRIDE)
message(STATUS "Overriding option")
set(GLFW_BUILD_EXAMPLES OFF CACHE BOOL "Build the GLFW example programs")
endif()
message(STATUS "OPT BEFORE =${GLFW_BUILD_EXAMPLES}")
add_subdirectory(subdir)
message(STATUS "OPT AFTER=${GLFW_BUILD_EXAMPLES}")
and subdir / CMakeLists.txt
option(GLFW_BUILD_EXAMPLES "Build the GLFW example programs" ON)
you will see the following (when run in build directory
Without command line parameters, the command option()
sets the variable
$ rm -rf *
$ cmake ..
...
-- OPT BEFORE =
-- OPT AFTER=ON
-- Configuring done
-- Generating done
Overload enable, command set()
cancel commandoption()
$ rm -rf *
$ cmake .. -DOVERRIDE=ON
...
-- Overriding option
-- OPT BEFORE =OFF
-- OPT AFTER=OFF
-- Configuring done
-- Generating done
You can also overload option()
directly on the command line.
$ rm -rf *
$ cmake .. -DGLFW_BUILD_EXAMPLES=OFF
...
-- OPT BEFORE =OFF
-- OPT AFTER=OFF
-- Configuring done
-- Generating done
Please note that every time I do rm -rf *
in the build directory. The value is GLFW_BUILD_EXAMPLES
cached in a file named CMakeCache.txt
. CMake will always use the values it finds there before anything set in the command set
or option
.
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