cmake ignores -D CMAKE_BUILD_TYPE=Debug

Question

I'm just trying to build a cmake project in debug-mode to enable asserts. I tried the following versions:

cmake -D CMAKE_BUILD_TYPE:STRING=Debug -L ../../
cmake -DCMAKE_BUILD_TYPE:STRING=Debug -L ../../
cmake -DCMAKE_BUILD_TYPE=Debug -L ../../

Unfortunately none of theese has the desired effect - that CMAKE_BUILD_TYPE is set to Debug (and therefore the NDEBUG-flag is not passed to gcc).

Additionally I added variable_watch(CMAKE_BUILD_TYPE) to my main CMakeLists.txt to check whether the value get's overridden somewhere. But the first output is a READ_ACCESS in my main Additionally I added variable_watch(CMAKE_BUILD_TYPE) to my main CMakeLists.txt and the value there already is Release.

Does someone have an idea why cmake ignores the configuration?

I'm using cmake version 2.8.7.

Answer 1

Ok, fgrep -R "CMAKE_BUILD_TYPE" finally found the problem for me. In some CMakeLists.txt-file I found something like that:

SET( CMAKE_BUILD_TYPE Release ... FORCE )

That overrides every user defined parameters (because of the FORCE).

What works for me is that:

IF( NOT CMAKE_BUILD_TYPE )
   SET( CMAKE_BUILD_TYPE Release ... FORCE )
ENDIF()

Thank's for your hints!

Answer 2

I assume that there is something wrong with your config..

I wrote a complete, simple example here: https://dl.dropboxusercontent.com/u/68798379/cmake-build-type.tar.bz2

cmake_minimum_required (VERSION 2.8)

project(playlib)

message("CMAKE_BUILD_TYPE = ${CMAKE_BUILD_TYPE}")

IF(CMAKE_BUILD_TYPE MATCHES Debug)
  message("Debug build.")
ELSEIF(CMAKE_BUILD_TYPE MATCHES Release)
  message("Release build.")
ELSE()
  message("Some other build type.")
ENDIF()

add_library(TESTLIB SHARED src/test.c)

When you execute cmake with

cmake -DCMAKE_BUILD_TYPE=Debug ../../

It gives the following output:

$ ./gen-linux.sh
-- The C compiler identification is GNU 4.8.2
-- The CXX compiler identification is GNU 4.8.2
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
CMAKE_BUILD_TYPE = Debug
Debug build.
-- Configuring done
-- Generating done
-- Build files have been written to: /home/wojci/stack-overflow/cmake-build-type/build/linux

It shows that CMAKE_BUILD_TYPE is being set from the command line and it being recognized in the CMakeLists.txt config.

What happens when you run it on your system using your version of CMake?