function(qt_create_nolink_target target dependee_target) if(NOT TARGET "${target}") message(FATAL_ERROR "${target} does not exist when trying to build a nolink target.") endif() get_target_property(type "${target}" TYPE) if(type STREQUAL EXECUTABLE) message(FATAL_ERROR "${target} must be a library of some kind.") endif() if(type STREQUAL OBJECT_LIBRARY) message(FATAL_ERROR "${target} must not be an object library.") endif() # Strip off the namespace prefix, so from Vulkan::Vulkan to Vulkan, and then append _nolink. string(REGEX REPLACE "^.*::" "" non_prefixed_target ${target}) set(nolink_target "${non_prefixed_target}_nolink") # Create the nolink interface target, assign the properties from the original target, # associate the nolink target with the same export which contains # the target that uses the _nolink target. # Also create a namespaced alias of the form ${target}::${target}_nolink which is used by # our modules. # Also create a Qt namespaced alias target, because when exporting via install(EXPORT) # Vulkan::Vulkan_nolink transforms into Qt6::Vulkan_nolink, and the latter needs to be an # accessible alias for standalone tests. if(NOT TARGET "${nolink_target}") add_library("${nolink_target}" INTERFACE) set(prefixed_nolink_target "${target}_nolink") # Whe configuring an example with qmake, if QtGui is built with Vulkan support but the # user's machine where Qt is installed doesn't have Vulkan, qmake doesn't fail saying # that vulkan is not installed. Instead it silently configures and just doesn't add # the include headers. # To mimic that in CMake, if the Vulkan CMake package is not found, we shouldn't fail # at generation time saying that the Vulkan target does not exist. Instead check with a # genex that the target exists to query the properties, otherwise just silently continue. # FIXME: If we figure out that such behavior should only be applied to Vulkan, and not the # other _nolink targets, we'll have to modify this to be configurable. set(target_exists_genex "$") set(props_to_set INTERFACE_INCLUDE_DIRECTORIES INTERFACE_SYSTEM_INCLUDE_DIRECTORIES INTERFACE_COMPILE_DEFINITIONS INTERFACE_COMPILE_OPTIONS INTERFACE_COMPILE_FEATURES) foreach(prop ${props_to_set}) set_target_properties( "${nolink_target}" PROPERTIES ${prop} $<${target_exists_genex}:$> ) endforeach() add_library(${prefixed_nolink_target} ALIAS ${nolink_target}) add_library("${INSTALL_CMAKE_NAMESPACE}::${nolink_target}" ALIAS ${nolink_target}) set(export_name "${INSTALL_CMAKE_NAMESPACE}${dependee_target}Targets") qt_install(TARGETS ${nolink_target} EXPORT ${export_name}) endif() endfunction()