Cmake variables for systemd are empty

Question

I want to start/stop a systemd service from within my C++ project. Therefore I like to use the systemd lib and headers provided. I'm using cmake for makefile generation. I'm trying to get systemd in cmake via

pkg_check_modules(SDBUS REQUIRED systemd)

which actually works as

message(STATUS "FOUND" ${SDBUS_FOUND}) returns 1.

However, all the other necessary vars created by cmake like

message(STATUS "LIBS" ${SDBUS_LIBRARIES})
message(STATUS "LIB_DIRS" ${SDBUS_LIBRARY_DIRS})
message(STATUS "LDFLAGS" ${SDBUS_LDFLAGS})
message(STATUS "LDFLAGS_OTHER" ${SDBUS_LDFLAGS_OTHER})
message(STATUS "INCLUDE DIRS" ${SDBUS_INCLUDE_DIRS})
message(STATUS "CFLAGS" ${SDBUS_CFLAGS})
message(STATUS "CFLAGS_OTHER" ${SDBUS_CFLAGS_OTHER})

are empty. Which leads to a linker error when compiling the project. Indeed when calling

pkg-config --libs systemd

it's empty as well. Anyone has any idea on how to solve that and why all these information is not available for systemd?

Answer 1

You should use

pkg_check_modules(SDBUS REQUIRED libsystemd)

Note the extra 'lib' prefix.