LINK_LIBRARIES_ONLY_TARGETS

New in version 3.23.

Enforce that link items that can be target names are actually existing targets.

Set this property to a true value to enable additional checks on the contents of the LINK_LIBRARIES and INTERFACE_LINK_LIBRARIES target properties, typically populated by target_link_libraries(). Checks are also applied to libraries added to a target through the INTERFACE_LINK_LIBRARIES_DIRECT properties of its dependencies. CMake will verify that link items that might be target names actually name existing targets. An item is considered a possible target name if:

• it does not contain a / or \, and

• it does not start in -, and

• (for historical reasons) it does not start in $ or `.

This property is initialized by the value of the CMAKE_LINK_LIBRARIES_ONLY_TARGETS variable when a non-imported target is created. The property may be explicitly enabled on an imported target to check its link interface.

In the following example, CMake will halt with an error at configure time because miLib is not a target:

set(CMAKE_LINK_LIBRARIES_ONLY_TARGETS ON)
add_library(myLib STATIC myLib.c)
add_executable(myExe myExe.c)
target_link_libraries(myExe PRIVATE miLib) # typo for myLib

In order to link toolchain-provided libraries by name while still enforcing LINK_LIBRARIES_ONLY_TARGETS, use an imported Interface Library with the IMPORTED_LIBNAME target property:

add_library(toolchain::m INTERFACE IMPORTED)
set_property(TARGET toolchain::m PROPERTY IMPORTED_LIBNAME "m")
target_link_libraries(myExe PRIVATE toolchain::m)

See also policy CMP0028.

Note

If INTERFACE_LINK_LIBRARIES contains generator expressions, its actual list of link items may depend on the type and properties of the consuming target. In such cases CMake may not always detect names of missing targets that only appear for specific consumers. A future version of CMake with improved heuristics may start triggering errors on projects accepted by previous versions of CMake.