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cmake
Lahiru Chandima
Lahiru Chandima

Reputation: 24068

What is the default build configuration of CMake?

In this answer, it says Debug is the default cmake build configuration.

But I have a different observation:

I have following in my CMakeLists.txt to choose debug and release versions of a lib according to the current build configuration.

target_link_libraries(MyApp debug Widgets_d)
target_link_libraries(MyApp optimized Widgets)

It seems that when I invoke cmake without specifying -DCMAKE_BUILD_TYPE, Widgets is used instead of Widgets_d (When I delete Widgets and try to build, Make complains that lib is not there). So that means by default the build configuration is optimized, not debug.

So what actually is the default build configuration? If it is debug, what could be wrong with my CMakeLists.txt?

Upvotes: 14

Views: 28428

Answers (2)

Adrian W
Adrian W

Reputation: 5026

If depends on whether you are using a single-configuration generator (Makefiles) or a multi-configuration generator (Visual Studio, XCode).

The link cited in the question is about a multi-configuration generator. When using a multi-configuration generator, the configuration variable CMAKE_BUILD_TYPE is ignored. To select the configuration to build, cmake allows the switch --config. In many cases, omitting --config builds a Debug configuration, but the current CMake documentation now clarifies that there is no specified default - it can even be empty.

However, when using a single-configuration generator, the switch --config is ignored. Only the configuration variable CMAKE_BUILD_TYPE is used to determine the build type. The default depends on the toolchain (see docs).

More background info on single- and multiconfiguration-generators in this answer.

Upvotes: 14

Mikhail Maltsev
Mikhail Maltsev

Reputation: 1678

target_link_libraries with optimized keyword corresponds to all configurations, which are not debug.

Try adding message(STATUS "Build type: ${CMAKE_BUILD_TYPE}") to your CMakeLists.txt to see the actual build type (I suppose it should be empty).

Upvotes: 11

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