cmake(1)
Frequently used variables
# Install location.
CMAKE_INSTALL_PREFIX=<path>
# Generate compile_commands.json?
CMAKE_EXPORT_COMPILE_COMMANDS={0,1}
# Project build type.
CMAKE_BUILD_TYPE={Debug, Release, RelWithDebInfo, MinSizeRel}
# C++ standard.
CMAKE_CXX_STANDARD={14,17,..}
PRIVATE
/ PUBLIC
/ INTERFACE
These modifier control where properties for a given target are visible.
PRIVATE
: Only for the target itself.INTERFACE
: Only for anyone linking against the target.PUBLIC
: For the target itself and anyone linking against it (effectivelyPRIVATE
+INTERFACE
).
The following gives an example for preprocessor definitions specified on a library target. This behaves in the same way for other properties like for example include directories.
# CMakeLists.txt
cmake_minimum_required(VERSION 3.14)
project(moose)
# -- LIBRARY
add_library(liba STATIC liba.cc)
target_compile_definitions(liba PUBLIC DEF_PUBLIC)
target_compile_definitions(liba PRIVATE DEF_PRIVATE)
target_compile_definitions(liba INTERFACE DEF_INTERFACE)
# -- APPLICATION
add_executable(main main.cc)
target_link_libraries(main liba)
> touch liba.cc; echo "int main() {}" > main.cc
> cmake -B build -S . -G Ninja
> ninja -C build -j1 --verbose
[1/4] /usr/bin/c++ -DDEF_PRIVATE -DDEF_PUBLIC [..] .../liba.cc
[2/4] [..]
[3/4] /usr/bin/c++ -DDEF_INTERFACE -DDEF_PUBLIC [..] .../main.cc
[4/4] [..]
find_package
[ref]
A small example to play with can be found in cmake/module.
find_package(Name MODULE)
Looks for FindName.cmake
in paths given by CMAKE_MODULE_PATH
and then builtin paths.
find_package(Name CONFIG)
Looks for name-config.cmake
or NameConfig.cmake
in paths given by
CMAKE_PREFIX_PATH
, or path given by Name_DIR
and then builtin paths.