How to list all CMake build options and their default values?

Question

How can I list cmake default build option in command-line?
I need to build OpenCV libraries from source. Before that, I want to know what are the default build settings.

Answer 1

cmake -LA

To list all option( and set( CACHE (cached) variables do:

mkdir build
cd build
cmake ..
cmake -LA | awk '{if(f)print} /-- Cache values/{f=1}'

Sample stdout:

AUTOGEMM_ARCHITECTURE:STRING=Hawaii
BLAS_DEBUG_TOOLS:BOOL=OFF
BLAS_DUMP_CLBLAS_KERNELS:BOOL=OFF
BLAS_KEEP_KERNEL_SOURCES:BOOL=ON
BLAS_PRINT_BUILD_ERRORS:BOOL=O

The -A switch also show options marked as advanced, so you will likely want to omit it when casually browsing the most useful options.

ccmake ncurses

sudo apt-get install cmake-curses-gui
ccmake ..

shows:

Tested in Ubuntu 16.10, cmake 3.5.2.

Answer 2

You can do cmake -LAH too. The H flag will provide you help for each option.

Answer 3

I do not know of an direct way to do it.

A way around this is to edit the main CMakeLists.txt and print at the end of the file the settings you are interested. The Variables where the most important cmake setting are stored are listed here:

I always print these variables at the end of my CMakeLists.txt to see the settings.

MESSAGE(STATUS "Build type: " ${CMAKE_BUILD_TYPE})
MESSAGE(STATUS "Library Type: " ${LIB_TYPE})
MESSAGE(STATUS "Compiler flags:" ${CMAKE_CXX_COMPILE_FLAGS})
MESSAGE(STATUS "Compiler cxx debug flags:" ${CMAKE_CXX_FLAGS_DEBUG})
MESSAGE(STATUS "Compiler cxx release flags:" ${CMAKE_CXX_FLAGS_RELEASE})
MESSAGE(STATUS "Compiler cxx min size flags:" ${CMAKE_CXX_FLAGS_MINSIZEREL})
MESSAGE(STATUS "Compiler cxx flags:" ${CMAKE_CXX_FLAGS})