CMake Intro

Notes:  directory structure:  cmake, cmake/Tutorial, cmake/Tutorial/MathLibs

1. File lists in cmake/Tutorial

CMakeLists.txt

TutorialConfig.h.in

tutorial.cxx

2. File lists in cmake/Tutorial/MathLibs

CMakeLists.txt

MathLibs.h

mysqrt.cxx

3. cmake/Tutorial/CMakeLists.txt

cmake_minimum_required (VERSION 2.6)
project (Tutorial)

# The version number.
set (Tutorial_VERSION_MAJOR 1)
set (Tutorial_VERSION_MINOR 0)

set(CMAKE_BUILD_TYPE DEBUG)
set(CMAKE_C_FLAGS "-O0 -ggdb")
set(CMAKE_C_FLAGS_DEBUG "-O0 -ggdb")
set(CMAKE_C_FLAGS_RELEASE "-O3")
set(CMAKE_CXX_FLAGS "-O0 -ggdb")
set(CMAKE_CXX_FLAGS_DEBUG "-O0 -ggdb")
set(CMAKE_CXX_FLAGS_RELEASE "-O3")

# configure a header file to pass some of the CMake settings
# to the source code
configure_file (
  "${PROJECT_SOURCE_DIR}/TutorialConfig.h.in"
  "${PROJECT_SOURCE_DIR}/TutorialConfig.h"
  )

# add the binary tree to the search path for include files
# so that we will find TutorialConfig.h
include_directories("${PROJECT_SOURCE_DIR}")

# should we use our own math functions?
option (USE_MYMATH
        "Use tutorial provided math implementation" ON)

# add the MathFunctions library?

#
if (USE_MYMATH)
  include_directories ("${PROJECT_SOURCE_DIR}/MathLibs")
  add_subdirectory (MathLibs)
  set (EXTRA_LIBS ${EXTRA_LIBS} MathLibs)
endif (USE_MYMATH)

# add the executable
add_executable (Tutorial.x tutorial.cxx)
target_link_libraries (Tutorial.x  ${EXTRA_LIBS})

4. cmake/Tutorial/MathLibs/CMakeLists.txt

add_library(MathLibs mysqrt.cxx)

5. Configure and Compile

do so  in cmake directory as the followings

cmake -DUSE_MYMATH=on Tutorial

make

6. others

add_library (core OBJECT ${SOURCES})

add_library (static STATIC $<TARGET_OBJECTS:core>)

add_library (shared SHARED $<TARGET_OBJECTS:core>)

The above will build static and shared library from the same set of object files.

This improves compilation time considerably as source files will be compiled

only once and used in multiple targets.