CMake:HowToUseExistingOSXFrameworks

CMake's framework detection mechanism is now complete. Here is a code snippet from a CMakeLists.txt file. Suppose we need the Carbon framework, Quicktime Framework and ApplicationServices.

IF(APPLE)
#SET(GUI_TYPE MACOSX_BUNDLE)
INCLUDE_DIRECTORIES ( /Developer/Headers/FlatCarbon )
FIND_LIBRARY(CARBON_LIBRARY Carbon)
FIND_LIBRARY(QUICKTIME_LIBRARY QuickTime )FIND_LIBRARY(APP_SERVICES_LIBRARY ApplicationServices )
MARK_AS_ADVANCED (CARBON_LIBRARY)
MARK_AS_ADVANCED (QUICKTIME_LIBRARY)
MARK_AS_ADVANCED (APP_SERVICES_LIBRARY)
SET(EXTRA_LIBS ${CARBON_LIBRARY} ${QUICKTIME_LIBRARY} ${APP_SERVICES_LIBRARY})
ENDIF (APPLE)

... Then later on in the file:

ADD_EXECUTABLE( ${MHDVIEWER_EXE_NAME} ${GUI_TYPE} ${PROJECT_SRCS} )
TARGET_LINK_LIBRARIES( ${MHDVIEWER_EXE_NAME} ${EXTRA_LIBS} )

As for the syntax of your #includes, you have two choices. Generally, OS X system frameworks are included as:

#include <Cocoa/Cocoa.h>
#include <OpenAL/al.h>

But portable libraries may recommend doing flat namespaces because not everybody uses the same directory name. For example, the OpenAL spec doesn't define where headers are located. Linux puts them in <AL/al.h>, OS X does <OpenAL/al.h>, and Windows doesn't put them in any directory so it is <al.h>. In theory, somebody else could screw this up even more and put it in <AL1.1/al.h>. Thus the 'portable' solution is:

#include "al.h"

CMake is really clever about the two cases, so if you have the usage first case, you want to do:

FIND_PATH(COCOA_INCLUDE_DIR Cocoa/Cocoa.h)

In the second case you want to do:

FIND_PATH(OPENAL_INCLUDE_DIR al.h)

CMake will set the include paths correctly depending on which style you specify.

This is an edited version of helpful posts from Mike Jackson and Eric Wing. -Drew Wagner