Building with Debug and Release Configurations using CMake

CMake is a powerful build system generator that allows you to create build configurations for your projects. One of the key features of CMake is its ability to generate build files for different configurations, such as debug and release builds. In this tutorial, we will explore how to use CMake to build your project with debug and release configurations.

Introduction to CMake Build Types

CMake provides several built-in build types that you can use to configure your build process. The most commonly used build types are:

Debug: This build type is used for debugging purposes and includes debugging symbols.
Release: This build type is used for releasing your project and optimizes the code for performance.
RelWithDebInfo: This build type is a combination of release and debug builds, providing some optimization while still including debugging symbols.
MinSizeRel: This build type optimizes the code for size, resulting in smaller binaries.

Running CMake with Different Build Types

To run CMake with a specific build type, you can use the -DCMAKE_BUILD_TYPE option. For example:

mkdir Release
cd Release
cmake -DCMAKE_BUILD_TYPE=Release ..
make

This will generate a release build of your project.

For debug builds, you can use the following command:

mkdir Debug
cd Debug
cmake -DCMAKE_BUILD_TYPE=Debug ..
make

Note that CMake will automatically detect and use the compiler appropriate for your different source files.

Specifying Debug and Release Flags

CMake provides several variables that allow you to specify flags for debug and release builds. For example, you can use the CMAKE_CXX_FLAGS_DEBUG and CMAKE_CXX_FLAGS_RELEASE variables to set flags for debug and release builds respectively.

Here is an example:

set(CMAKE_CXX_FLAGS_DEBUG_INIT "-Wall")
set(CMAKE_CXX_FLAGS_RELEASE_INIT "-Wall")

Alternatively, you can use the add_compile_options function to add compile options for specific build configurations. For example:

add_compile_options(
  "-Wall" "-Wpedantic" "-Wextra" "-fexceptions"
  "$<CONFIG:DEBUG>:-O0;-g3;-ggdb>"
)

This will add the specified warnings to all build types, but only the given debugging flags to the debug build.

Using Target Properties

CMake also provides target properties that allow you to specify flags and options for specific targets. For example:

add_library(foobar)

target_compile_definitions(foobar PRIVATE
    $<CONFIG:Debug>:
        FOOBAR_DEBUG=1
    >
)

This will add a compile definition FOOBAR_DEBUG with value 1 to the foobar target only for debug builds.

Compiling Source Files with Specific Compilers

By default, CMake uses the file extension to determine which compiler to use. For example, files with the .c extension are compiled with the C compiler, while files with the .cpp extension are compiled with the C++ compiler.

However, you can override this behavior by using the set_source_files_properties function. For example:

set_source_files_properties(yourfile.c LANGUAGE CXX)

This will compile the yourfile.c file with the C++ compiler instead of the C compiler.

Conclusion

In conclusion, CMake provides a flexible and powerful way to build your projects with different configurations. By using the -DCMAKE_BUILD_TYPE option, you can easily switch between debug and release builds. Additionally, CMake provides several variables and functions that allow you to specify flags and options for specific build configurations and targets.

By following this tutorial, you should now have a good understanding of how to use CMake to build your projects with debug and release configurations.