Targets, Properties, And More¶

Target Types ¶

Two basic types: ADD_EXECUTABLE() and ADD_LIBRARY()
ADD_EXECUTABLE() is not relevant …
- Only entry point into dependency graph
- ⟶ does not propagate anything to dependers
- There are no dependers

ADD_LIBRARY() …

Type	Description
Normal library	`STATIC` (default), `SHARED`, `MODULE`. Has sources to be built.
Object libraries	Technically much like normal libraries, but not an archive or shared object (only virtual, implemented by CMake)
Interface libraries	No sources; only there to propagate properties to dependers, and to have further dependencies on their own.

(For a complete list see ADD_LIBRARY())

Target function	Property name	Description	Documentation
`TARGET_COMPILE_DEFINITIONS()`	`COMPILE_DEFINITIONS`	Macros set on the compiler command line (`-Dname=value`)	TARGET_COMPILE_DEFINITIONS()
`TARGET_COMPILE_OPTIONS()`	`COMPILE_OPTIONS`	Non-macro compiler flags/options	TARGET_COMPILE_OPTIONS()
`TARGET_INCLUDE_DIRECTORIES()`	`INCLUDE_DIRECTORIES`	Include directories	TARGET_INCLUDE_DIRECTORIES()
`TARGET_LINK_LIBRARIES()`	(Much more complicated, see documentation)	Dependencies, in the widest sense	TARGET_LINK_LIBRARIES()

PUBLIC propagated to dependers
- Dependency through #include <other.h> in a header file ⟶ all includers need to know
- blacklist availability in approach 2 (but only if blacklist has compiled code)
- PUBLIC only possible when target has compiled code
PRIVATE does not propagate
- For example, one might structure a target’s source code into src/, private-inc/, and public-inc/ ⟶ private-inc/ would be TARGET_INCLUDE_DIRECTORIES(... PRIVATE ...)
- For example, TARGET_COMPILE_DEFINITIONS() for target-local compilation only
INTERFACE propagated to dependers
- Just like PUBLIC - except that PUBLIC is not possible on INTERFACE targets (e.g. header-only libraries)
- Asymmetric; smells like it does in many corners of CMake
- Documentation has no clear explanation. Exceptions, and paragraph-long explanations.