I hope that all open-source libraries switch to this style sooner rather than later so you can easily include them in your build-trees. It pretty much is the combination of PRIVATE and INTERFACE – whenever you’re temped to put something in both of those, put it in PUBLIC instead. The PUBLIC keyword is used when definitions and includes are relevant for the own and dependent libraries. For include directories, one common usage is to set the own source directory with INTERFACE if you keep your headers and source files in the same folder. dll interface differently for compilation and usage. The INTERFACE keyword is a bit more curious: For example, with definitions, you can use it to define your. It’s good practice to favor PRIVATE to avoid “leaking” dependencies so they won’t stack up in the dependent libraries and bring down your compile times. your *.cpp and *.c files and internal headers. Typically, you’d use the PRIVATE keyword for includes and definitions that are exclusively used in you implementation, i.e. Now here’s a program that wants to use that:Ĭool_tool can just #include "cool_feature.hpp" without knowing exactly where it is located in the source tree or without having to worry about setting up the boost includes for itself! Pretty neat! PRIVATE, PUBLIC and INTERFACE Here’s a small example of a library that uses Boost in its headers and therefore wishes to have its clients setup those directories as well: There’s also the PRIVATE keyword that can be used to avoid adding the settings to all dependent targets. To do this, you need to use target_include_directories and target_compile_definitions with the PUBLIC or INTERFACE keywords on your targets. The gist is this: Using target_link_libraries to link A to an internal target B will not only add the linker flags required to link to B, but also the definitions, include paths and other settings – even transitively – if they are configured that way. Of course, it’s all in the CMake documentation, but mentioned implicitly at best. The ones that initially put me on the right track were The Ultimate Guide to Modern CMake and CMake – Introduction and best practices. But information on this is pretty scarce on the web. It turns out there’s actually a pretty elegant solution built into CMake, which centers around target_link_libraries. All these homegrown solutions work, but they are rather clumsy and don’t work well when integrating libraries not written in that same convention. Other projects defined “interface” files for each library that could be included by other targets. I’ve seen projects tackle this problem in various ways – for example by defining specifically named variables for each library and using that for their clients. Of course, this is all heavily order-dependent – so the build system breaks as soon as you make an ever so subtle change to the directory layout. I’d use the include_directories, add_definitions and add_compile_options command in the top-level or in mid-level CMakeLists.txt files just to get the whole thing to compile. Create aĬMakeLists.txt file in the Step1 directory that looks like:Įnable_testing() # does the application run add_test( NAME Runs COMMAND Tutorial 25 ) # does the usage message work? add_test( NAME Usage COMMAND Tutorial ) set_tests_properties( Usage PROPERTIES PASS_REGULAR_EXPRESSION "Usage.*number" ) # define a function to simplify adding tests function( do_test target arg result ) add_test( NAME Comp $ /Table.One thing that has eluded me in the past was how to efficiently manage dependencies of different components within one CMake project. ![]() This will be the starting point for our tutorial. The most basic project is an executable built from source code files.įor simple projects, a three line CMakeLists.txt file is all that is Tutorial examples are progressive so that each step provides the complete Its own subdirectory containing code that may be used as a starting point. Help/guide/tutorial directory of the CMake source code tree. The tutorialĭocumentation and source code for examples can be found in the Work together in an example project can be very helpful. ![]() The CMake tutorial provides a step-by-step guide that covers common build Adding a Version Number and Configured Header FileĪdding Usage Requirements for Library (Step 3)Īdding a Custom Command and Generated File (Step 6)
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