====== CMake ======

[[https://cmake.org/Wiki/CMake_Useful_Variables]]
[[http://www.vtk.org/Wiki/CMake_Cross_Compiling#Setting_up_the_system_and_toolchain]]

==== verbose build ====

=== Method 1 ===

<file cmake CMakeList.txt>
set(CMAKE_VERBOSE_MAKEFILE ON)
</file>

=== Method 2 ===

<code bash>make VERBOSE=1</code>

=== Method 3 ===

<code bash>cmake -DCMAKE_VERBOSE_MAKEFILE:BOOL=ON $path_to_project_source</code>


==== multiline strings ====

Use 2 space indentation
<code>
message(STATUS "This is a very long
  message spanning on
  several lines
")
</code>

==== add all *.c files ====

<code cmake>
cmake_minimum_required(VERSION 2.8)

file(GLOB helloworld_SRC
    "*.h"
    "*.cpp"
)

add_executable(helloworld ${helloworld_SRC})
</code>


==== linker flags ====
Check:
  * CMAKE_EXE_LINKER_FLAGS
  * CMAKE_MODULE_LINKER_FLAGS
  * CMAKE_SHARED_LINKER_FLAGS
  * CMAKE_STATIC_LINKER_FLAGS

<code>
set (CMAKE_EXE_LINKER_FLAGS "-Wl,--unresolved-symbols=ignore-in-object-files") 
</code>

==== debug build ====
<code bash>
mkdir Debug
cd Debug
cmake -DCMAKE_BUILD_TYPE=Debug ..
make
</code>
<code bash>
mkdir Release
cd Release
cmake -DCMAKE_BUILD_TYPE=Release ..
make
</code>

<code cmake>
set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -Wall")
set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -Wall")
</code>

==== libraries ====
<code cmake>
add_executable(ws2812 ${COMMON_SOURCES} ${TARGET_SOURCES})
target_link_libraries(ws2812 rpi_ws281x)

set(RPI_WS281X_SOURCES
    mailbox.c
    ws2811.c
    pwm.c
    dma.c
    rpihw.c
)

add_library(rpi_ws281x STATIC ${RPI_WS281X_SOURCES})
</code>

=== find_package vs find_library ===
  * **find_package** Loads settings for external project. Try to configure all variables related to package (headers, paths)
    * module: package_name.cmake (or shipped with CMake /usr/share/cmake/Modules/FindPackage_name.cmake)
    * config: package_nameConfig.cmake or package_name-.cmake
  * **find_library**
  *