CMake: Set different name for #cmakedefine variable - c++

Question

I know you can use CMake's configure_file to make CMake variables available to your program. For example, I can use
#define ${CMAKE_BUILD_TYPE}
resulting in
#define Release
However, to keep my code more readible, I would prefer to define
#define BUILD_TYPE_RELEASE
Is there a simple way to achieve this?

Answer 1

Here is a fairly simple way to solve it:
In CMakesLists.txt:
if (NOT CMAKE_BUILD_TYPE)
set (CMAKE_BUILD_TYPE Release)
endif (NOT CMAKE_BUILD_TYPE)
string (TOUPPER ${CMAKE_BUILD_TYPE} BUILD_TYPE_NAME)
configure_file (config.h.in config.h)
And in config.h.in:
#define BUILD_TYPE_${BUILD_TYPE_NAME}
I am, however, still curious if there is a more elegant solution.

Answer 2

This is more a question of your preferred programming style (configuration files vs. compiler definitions).
In your case I would use add_definitions() or directly modify/append COMPILE_DEFINITIONS directory property (using generator expressions also supports multi-configuration environments):
set_property(
DIRECTORY
APPEND
PROPERTY
COMPILE_DEFINITIONS "BUILD_TYPE_$<UPPER_CASE:$<CONFIG>>"
)
Most simplified Debug/Release Check
You can also check what compiler definitions CMake does pre-define. Without having to modify/add something to your CMakeLists.txt files you could simply check for NDEBUG definition (set for Release builds across platforms) in you C/C++ code:
#ifdef NDEBUG
...
#endif
References
CMake: How to pass preprocessor macros
How to check if a CMake build directory build type is Debug or Release?
What predefined macro can be used to detect debug build with clang?