Set Build Type using CMake

When working with CMake-based projects, one important aspect to control is the build configuration. CMake supports multiple build types that influence compiler options, optimizations, and whether debug information is generated. Choosing the right build type ensures that you can debug effectively during development while producing optimized binaries for release.

By default, CMake leaves the build type unset when generating project files for single-configuration generators (such as Unix Makefile or Ninja). This can be confusing because, unless explicitly specified, your project might not have the optimization or debugging options you expect.

Let's say we have a simple CMakeLists.txt file:

cmake_minimum_required(VERSION 3.27)
project(myapp)

set(CMAKE_CXX_STANDARD 17)

add_executable(${PROJECT_NAME} main.cpp)

We can use the CMAKE_BUILD_TYPE variable to specify build type during configuration. For instance, if you want to build in release mode with optimizations enabled, use:

cmake -S . -B build -DCMAKE_BUILD_TYPE=Release

CMake defines several standard build types out of the box:

• Debug - compiles with no optimization and includes full debug information, useful for step-by-step debugging.
• Release - enables compiler optimizations and omits debug info, producing smaller and faster executables.
• RelWithDebInfo - optimized build that also includes debug symbols, a good compromise for profiling and troubleshooting.
• MinSizeRel - focuses on minimizing binary size while still applying optimizations.