How to Use Transitive Shared Dependency In Cmake?

In CMake, transitive shared dependencies are used when a library depends on another library that is also a shared library. This means that when linking against the first library, the linker should also link against the shared libraries the first library depends on.

To use transitive shared dependencies in CMake, you need to set the INTERFACE_LINK_LIBRARIES property for the library that has the shared dependencies. This property should include the shared libraries that the library depends on.

For example, if you have libraryA that depends on libraryB and libraryB is a shared library, you would set the INTERFACE_LINK_LIBRARIES property of libraryA to include libraryB. This way, when linking against libraryA, CMake will also link against libraryB automatically.

To set the INTERFACE_LINK_LIBRARIES property, you can use the target_link_libraries command in your CMakeLists.txt file. For example:

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target_link_libraries(libraryA INTERFACE libraryB)

This will ensure that when linking against libraryA, CMake will also link against libraryB as a shared dependency.

How to find transitive shared dependencies in cmake?

To find transitive shared dependencies in CMake, you can use the find_package command along with the PUBLIC and PRIVATE keywords in the target_link_libraries command.

Here's a step-by-step guide on how to do this:

1. Use the find_package command to locate the shared library you want to link to. For example:

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find_package(Boost REQUIRED COMPONENTS filesystem)

1. Use the target_link_libraries command with the PUBLIC keyword to indicate that this dependency should be propagated to any targets that link to the current target. For example:

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target_link_libraries(my_target PUBLIC Boost::filesystem)

1. Use the PUBLIC keyword when declaring dependencies in your library's CMakeLists.txt file. For example:

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add_library(my_library SHARED my_source.cpp)
target_link_libraries(my_library PUBLIC Boost::filesystem)

This way, any targets that link to my_library will automatically inherit the transitive dependency on Boost::filesystem.

What is a shared dependency in cmake?

In CMake, a shared dependency refers to a dependency on an external library or component that is shared among multiple targets within a CMake project. This means that multiple targets in the project rely on the same external library for functionality or resources.

Shared dependencies are specified in the CMakeLists.txt files of the targets that need to use them, typically through the target_link_libraries() function. This allows for better organization and management of dependencies, as the shared dependency only needs to be specified once and can be easily updated or replaced if needed.

Using shared dependencies in CMake helps to reduce duplication of code, streamline the build process, and ensure that all targets within a project are using the same version of a library or component.

What is the difference between transitive and non-transitive shared dependencies in cmake?

In CMake, transitive shared dependencies are dependencies of a target that will also be linked to when the target is linked from another target. This means that if Target A depends on Library B, and Target C depends on Target A, then Target C will also automatically link to Library B.

On the other hand, non-transitive shared dependencies are dependencies that are not automatically propagated to targets that depend on the target with the dependency. In the example above, if Library B is declared as a non-transitive shared dependency of Target A, then Target C will not automatically link to Library B when it depends on Target A.

In summary, transitive shared dependencies are automatically propagated to other targets that depend on the target with the dependency, while non-transitive shared dependencies are not automatically propagated.

How to install transitive shared dependencies in cmake?

To install transitive shared dependencies in CMake, you can use the find_package command to locate and import the required dependencies.

Here's a basic example of how to install transitive shared dependencies using CMake:

1. Add the find_package command in your CMakeLists.txt file to locate and import the required dependencies. For example:

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find_package(Boost COMPONENTS filesystem system REQUIRED)

This command will search for the Boost libraries and import the required components into your project.

1. Use the imported target in your CMake target to link against the shared dependencies. For example:

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add_executable(my_project main.cpp)
target_link_libraries(my_project Boost::filesystem Boost::system)

This will link your executable with the Boost filesystem and system libraries.

1. Make sure to specify the installation destination for the dependencies in your CMakeLists.txt file by using the install(TARGETS ...) command. For example:

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install(TARGETS my_project
    RUNTIME DESTINATION bin
)

This command will install your project executable in the specified destination folder.

1. Build your project using CMake and the shared dependencies will be automatically installed alongside your project executable.

By following these steps, you can easily install transitive shared dependencies in CMake for your project.

How to specify transitive shared dependencies in a CMakeLists.txt file?

To specify transitive shared dependencies in a CMakeLists.txt file, you can use the target_link_libraries command with the PUBLIC keyword for each target that needs to link to a shared library.

For example, if you have two shared libraries lib1 and lib2, and a target my_target that depends on lib1, which in turn depends on lib2, you can specify their dependencies as follows:

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# CMakeLists.txt

# Define the shared libraries
add_library(lib2 SHARED lib2.cpp)
add_library(lib1 SHARED lib1.cpp)
target_link_libraries(lib1 PUBLIC lib2)

# Define the target
add_executable(my_target main.cpp)
target_link_libraries(my_target PRIVATE lib1)

In this example, my_target links to lib1 with the PRIVATE keyword, meaning that lib1 is a private dependency of my_target and will not be propagated to other targets that link to my_target. However, because lib1 links to lib2 with the PUBLIC keyword, any target that links to lib1 will automatically link to lib2 as well.

By using the PUBLIC keyword in the target_link_libraries command for shared libraries, you can specify transitive shared dependencies that will be automatically propagated to targets that depend on those libraries.