# ECMFindModuleHelpers

Helper macros for find modules: ecm_find_package_version_check(), ecm_find_package_parse_components() and ecm_find_package_handle_library_components().

    ecm_find_package_version_check(<name>)

Prints warnings if the CMake version or the project’s required CMake version is older than that required by extra-cmake-modules.

    ecm_find_package_parse_components(<name>
        RESULT_VAR <variable>
        KNOWN_COMPONENTS <component1> [<component2> [...]]
        [SKIP_DEPENDENCY_HANDLING])

This macro will populate <variable> with a list of components found in <name>_FIND_COMPONENTS, after checking that all those components are in the list of KNOWN_COMPONENTS; if there are any unknown components, it will print an error or warning (depending on the value of <name>_FIND_REQUIRED) and call return().

The order of components in <variable> is guaranteed to match the order they are listed in the KNOWN_COMPONENTS argument.

If SKIP_DEPENDENCY_HANDLING is not set, for each component the variable <name>_<component>_component_deps will be checked for dependent components. If <component> is listed in <name>_FIND_COMPONENTS, then all its (transitive) dependencies will also be added to <variable>.

    ecm_find_package_handle_library_components(<name>
        COMPONENTS <component> [<component> [...]]
        [SKIP_DEPENDENCY_HANDLING])
        [SKIP_PKG_CONFIG])

Creates an imported library target for each component. The operation of this macro depends on the presence of a number of CMake variables.

The <name>_<component>_lib variable should contain the name of this library, and <name>_<component>_header variable should contain the name of a header file associated with it (whatever relative path is normally passed to ‘#include’). <name>_<component>_header_subdir variable can be used to specify which subdirectory of the include path the headers will be found in. ecm_find_package_components() will then search for the library and include directory (creating appropriate cache variables) and create an imported library target named <name>::<component>.

Additional variables can be used to provide additional information:

If SKIP_PKG_CONFIG, the <name>_<component>_pkg_config variable is set, and pkg-config is found, the pkg-config module given by <name>_<component>_pkg_config will be searched for and used to help locate the library and header file. It will also be used to set <name>_<component>_VERSION.

Note that if version information is found via pkg-config, <name>_<component>_FIND_VERSION can be set to require a particular version for each component.

If SKIP_DEPENDENCY_HANDLING is not set, the INTERFACE_LINK_LIBRARIES property of the imported target for <component> will be set to contain the imported targets for the components listed in <name>_<component>_component_deps. <component>_FOUND will also be set to false if any of the compoments in <name>_<component>_component_deps are not found. This requires the components in <name>_<component>_component_deps to be listed before <component> in the COMPONENTS argument.

The following variables will be set:

`<name>_TARGETS`
  the imported targets
`<name>_LIBRARIES`
  the found libraries
`<name>_INCLUDE_DIRS`
  the combined required include directories for the components
`<name>_DEFINITIONS`
  the “other” CFLAGS provided by pkg-config, if any
`<name>_VERSION`
  the value of `<name>_<component>_VERSION` for the first component that has this variable set (note that components are searched for in the order they are passed to the macro), although if it is already set, it will not be altered

Note that these variables are never cleared, so if ecm_find_package_handle_library_components() is called multiple times with different components (typically because of multiple find_package() calls) then `<name>_TARGETS`, for example, will contain all the targets found in any call (although no duplicates).

Since pre-1.0.0.