target_link_libraries
: Link a target to given libraries.target_link_libraries(<target> [item1 [item2 [...]]]
[[debug|optimized|general] <item>] ...)
Specify libraries or flags to use when linking a given target. The named <target> must have been created in the current directory by a command such as add_executable or add_library. The remaining arguments specify library names or flags.
If a library name matches that of another target in the project a dependency will automatically be added in the build system to make sure the library being linked is up-to-date before the target links. Item names starting with '-', but not '-l' or '-framework', are treated as linker flags.
A "debug", "optimized", or "general" keyword indicates that the library immediately following it is to be used only for the corresponding build configuration. The "debug" keyword corresponds to the Debug configuration (or to configurations named in the DEBUG_CONFIGURATIONS global property if it is set). The "optimized" keyword corresponds to all other configurations. The "general" keyword corresponds to all configurations, and is purely optional (assumed if omitted). Higher granularity may be achieved for per-configuration rules by creating and linking to IMPORTED library targets. See the IMPORTED mode of the add_library command for more information.
Library dependencies are transitive by default. When this target is linked into another target then the libraries linked to this target will appear on the link line for the other target too. See the LINK_INTERFACE_LIBRARIES target property to override the set of transitive link dependencies for a target.
target_link_libraries(<target> LINK_INTERFACE_LIBRARIES
[[debug|optimized|general] <lib>] ...)
The LINK_INTERFACE_LIBRARIES mode appends the libraries to the LINK_INTERFACE_LIBRARIES and its per-configuration equivalent target properties instead of using them for linking. Libraries specified as "debug" are appended to the the LINK_INTERFACE_LIBRARIES_DEBUG property (or to the properties corresponding to configurations listed in the DEBUG_CONFIGURATIONS global property if it is set). Libraries specified as "optimized" are appended to the the LINK_INTERFACE_LIBRARIES property. Libraries specified as "general" (or without any keyword) are treated as if specified for both "debug" and "optimized".
The library dependency graph is normally acyclic (a DAG), but in the case of mutually-dependent STATIC libraries CMake allows the graph to contain cycles (strongly connected components). When another target links to one of the libraries CMake repeats the entire connected component. For example, the code
add_library(A STATIC a.c)
add_library(B STATIC b.c)
target_link_libraries(A B)
target_link_libraries(B A)
add_executable(main main.c)
target_link_libraries(main A)
links 'main' to 'A B A B'. (While one repetition is usually sufficient, pathological object file and symbol arrangements can require more. One may handle such cases by manually repeating the component in the last target_link_libraries call. However, if two archives are really so interdependent they should probably be combined into a single archive.)