How to Share Properties Across Multiple Targets In Cmake?

In CMake, sharing properties across multiple targets can be achieved using generator expressions. Generator expressions allow for conditional evaluation based on various criteria, such as target platform or compiler features, to set properties dynamically.

To share properties across multiple targets, you can use generator expressions in the set_target_properties function when configuring each target. For example, to set a specific compiler flag for multiple targets, you can use a generator expression to conditionally set the flag based on the target type.

Another approach to sharing properties is to create custom functions or macros that encapsulate the logic for setting common properties across targets. By defining a consistent interface for setting properties, you can easily apply the same configuration to multiple targets without duplicating code.

Overall, sharing properties across multiple targets in CMake requires strategic use of generator expressions and custom functions to ensure a clean and maintainable configuration for your project.

How to override shared properties for specific targets in CMake?

To override shared properties for specific targets in CMake, you can use the set_target_properties command to set the properties of individual targets. Here's an example:

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# Set common properties for all targets
set(CMAKE_CXX_STANDARD 11)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

# Create target foo
add_executable(foo foo.cpp)
set_target_properties(foo PROPERTIES CXX_STANDARD 14)

# Create target bar
add_executable(bar bar.cpp)
set_target_properties(bar PROPERTIES CXX_STANDARD 17)

In this example, we first set the common properties for all targets using set(). Then, for each individual target (foo and bar), we use set_target_properties to override the CXX_STANDARD property specifically for that target.

You can also use generator expressions to set properties conditionally based on variables or target properties. For example:

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# Set common properties for all targets
set(CMAKE_CXX_STANDARD 11)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

# Create target foo
add_executable(foo foo.cpp)
set_target_properties(foo PROPERTIES CXX_STANDARD $<$<BOOL:${FOO_USE_CXX_14}>:14>)

In this example, the CXX_STANDARD property for the foo target is set to 14 only if the FOO_USE_CXX_14 variable is set to TRUE. You can customize these generator expressions based on your specific needs to override shared properties for specific targets in CMake.

What is the relationship between shared properties and transitive dependencies in CMake?

In CMake, shared properties are properties that affect the behavior or configuration of a target or project and can be inherited by dependencies of that target. Transitive dependencies, on the other hand, are dependencies of a target that are not directly specified but are required by the direct dependencies.

The relationship between shared properties and transitive dependencies in CMake is that shared properties can be propagated to transitive dependencies. This means that if a target has a certain shared property set, then that property is also applied to all of its transitive dependencies. This allows for easy configuration and consistency of properties across multiple targets in a CMake project.

What is the most efficient way to propagate properties in CMake?

The most efficient way to propagate properties in CMake is to use the target_compile_options, target_compile_definitions, target_include_directories, and target_link_libraries commands. These commands allow you to set properties for a specific target, such as a library or executable, and have those properties automatically propagated to any targets that link against it.

For example, if you set compile options or include directories for a particular library target using target_compile_options or target_include_directories, any executable or other target that links against that library will automatically inherit those properties.

Additionally, you can use generator expressions in CMake to conditionally propagate properties based on the configuration or platform. This can help optimize your build process and ensure that the correct properties are applied to each target.

Overall, using the target_* commands and generator expressions in CMake is the most efficient way to propagate properties and ensure consistent configuration across all targets in your project.