Some variables have special siblings which have a configuration in their name and are used only when the chosen configuration matches that name.įor example, CMAKE_CXX_FLAGS holds flags passed to the compiler for all configurations of all C++ artifacts, while CMAKE_CXX_FLAGS_DEBUG holds flags passed to the compiler (in addition to CMAKE_CXX_FLAGS) for only debug configurations of all C++ artifacts.The configuration has implications throughout the project. builds that are colloquially called "debug" and "release", but that distinction is independent of (albeit often correlated with) the configuration. The set of possible variations includes linking against different builds of dependencies.Īrtifacts may have "debug" and "release" builds, i.e. Recalling my earlier vocabulary, an artifact is a library or executable, and any variation in the construction of that artifact creates a uniquely identifiable build of the artifact, whether or not it changes the artifact's ABI. The configuration is a property of the build step. Now, with a single-configuration generator, we know what that configuration will be,īut it still doesn't make sense to think of the configuration as a property of the project. When using CMake to build, we build a configuration. What does it mean to talk about the configuration? Whenever I use the term configuration, I am referring to this choice, however it was made. Visual Studio 16 2019), the configuration is chosen at build time by the command-line option -config. The configuration is chosen at configure time by the CMAKE_BUILD_TYPE variable.įor multi-configuration generators (e.g. These two terms are often used interchangeably, but I will stick to configuration here.įor single-configuration generators (e.g. In CMake, a build type or configuration is a name. I have tried and will continue to try to keep the ideas general, but this post is colored very specifically by my experience with CMake. With no knowledge or concern of the underlying build system.ĬMake is the build system I have in the back of my mind as I write this series.
Cmake debug build install#
Which lets users configure, build, test, and install projects in a cross-platform way by interacting with CMake only, I can already hear the shouts that it is not a build system, but a build system generator,īut that stopped being the case in my opinion when they added cmake -build in version 2.8,
To the point of being a de facto standard. Up to this point, I have tried to avoid fixating on any particular build system,īecause I believe it is the one most widely used in the community, I gave an example of mixing debug builds of some dependencies with release builds of other dependencies in order to aid debugging of some components without paying the cost of slowing down all components.īut I've never actually seen it in practice,Īnd in my experience, it is difficult to achieve with CMake. dependents, to choose which build they use for each of the dependencies in their dependency graph. Recall that I want to make it easy for library users, i.e. In this post, I want to talk about the trouble with build types or configurations in CMake. In the second post, I explained the difference between local and global compiler flags. In the first post, I described my vision and introduced a vocabulary for this series.
Cmake debug build code#
It produces fully optimized code, but also creates the symbol table and the debug metadata to give the debugger as much input as it is possible to map the execution back to the original code at any time.Ĭode build with RelwithDebInfo mode should not have it’s performance degraded in comparison to Release mode, as the symbol table and debug metadata that are generated do not live in the executable code section, so they should not affect the performance when the code is run without a debugger attached.This is the third post in a series on C++ developer experience. The difference between Debug and RelwithDebInfo modes is that RelwithDebInfo optimizes the code similarly to the behavior of Release mode. Modify as follows your cmake command to set the compilation mode to RelWithDebInfo (optimized code with debug symbols): cmake -DCMAKE_BUILD_TYPE=RelWithDebInfo Bonus material: Modify as follows your cmake command to set the compilation mode to Debug (non-optimized code with debug symbols): cmake -DCMAKE_BUILD_TYPE=Debug Solution 1: Modify the CMakeLists.txt fileĪdd the following line to your CMakeLists.txt file to set the compilation mode to Debug (non-optimized code with debug symbols): set(CMAKE_BUILD_TYPE Debug)Īdd the following line to your CMakeLists.txt file to set the compilation mode to RelWithDebInfo (optimized code with debug symbols): set(CMAKE_BUILD_TYPE RelWithDebInfo) Solution 2: Add a command line argument to your cmake command:
25 April 2017 in C / C++ / Programming tagged cmake / debug / debug metadata / gdb / RelwithDebInfo / symbol table by Tux
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