When using CMake, the options are typically specified before the filename when invoking the cmake command. However, if you need to force CMake to put the options after the filename, you can do so by simply rearranging the order of the arguments in the command line.
For example, instead of running:
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cmake -DVAR1=ON -DVAR2=OFF path/to/source
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You can run:
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cmake path/to/source -DVAR1=ON -DVAR2=OFF
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By putting the options after the filename, you can achieve the desired behavior of forcing CMake to recognize the options in the specified order.
What is the relationship between options and targets in cmake?
In CMake, targets are individual build artifacts, such as executables or libraries, that are created by the build system. Options, on the other hand, are variables that can be set in the CMakeLists.txt files to control the behavior of the build process.
Options can affect how a target is built by specifying compiler flags, linker options, or other build options that apply to all targets. Targets can also have properties that can be set using options to customize the behavior of the target.
Overall, options and targets in CMake are closely related as options can be used to configure how targets are built and customize their behavior.
What is the significance of option order in cmake?
In CMake, the order of options specified in CMakeLists.txt files is significant because it determines the behavior and configuration of the CMake build system. Options such as compiler flags, build type, source files, and dependencies must be specified in a specific order to ensure that the build system is configured correctly.
For example, specifying the compiler flags before setting the source files may cause the compiler flags to not be applied to the source files, resulting in compilation errors. Additionally, certain options may depend on other options being set or configured beforehand, so the order in which these options are specified can affect the overall behavior of the build system.
In general, it is important to follow the correct order of options in CMakeLists.txt files to ensure that the CMake build system functions correctly and produces the desired output.
What is the difference between explicit and implicit option placement in cmake?
In CMake, option placement refers to where options are specified within the CMakeLists.txt file.
Explicit option placement means that options are directly specified within the CMakeLists.txt file where they are used. This can make the code clearer and easier to read, as the options are directly associated with the targets or features they affect.
Implicit option placement, on the other hand, means that options are specified globally in the CMakeLists.txt file or in a separate configuration file, rather than directly where they are used. This can make the code more concise, but may also make it harder to understand the relationship between options and the targets they affect.
Overall, explicit option placement is generally recommended as it leads to more readable and maintainable CMake code.