CMake:How To Find Installed Software

If your software uses external libraries (i.e. libraries not coming with your software), you don't know in advance where its headers and libraries will be located on the system where your software will be compiled. Depending on the location appropriate include directories and library search paths will have to be added to the compile commands.

CMake helps you with this by providing so-called modules. Let's say you want to use the PNG-Library.

FIND_PACKAGE(PNG)

IF(PNG_FOUND)
   INCLUDE_DIRECTORIES(${PNG_INCLUDE_DIR})

   ADD_EXECUTABLE(imageviewer main.c image.c)
   TARGET_LINK_LIBRARIES(imageviewer ${PNG_LIBRARY})

ENDIF(PNG_FOUND)

Every module is provided in the form Find<name>.cmake, they are located in the CMake module directory, on UNIX usualy /usr/local/share/CMake/Modules/ It is then used in the CMakeLists.txt with the FIND_PACKAGE(<name>) command. For details see the regular CMake documentation. Every module will define the following variables:

• <name>_FOUND
• <name>_INCLUDE_DIR or <name>_INCLUDES
• <name>_LIBRARY or <name>_LIBRARIES