sd-bus — A lightweight D-Bus IPC client library
#include <systemd/sd-bus.h>
pkg-config --cflags --libs libsystemd 
sd-bus.h is part of
    libsystemd(3) and
    provides an implementation of a D-Bus IPC client. See
    https://www.freedesktop.org/software/dbus/
    for more information about D-Bus IPC.
See
for more information about the functions available.
The busctl(1) tool makes the functionality implemented by sd-bus available from the command line.
Functions described here are available as a shared
  library, which can be compiled against and linked to with the
  libsystemd pkg-config(1)
  file.
The code described here uses
  getenv(3),
  which is declared to be not multi-thread-safe. This means that the code calling the functions described
  here must not call
  setenv(3)
  from a parallel thread. It is recommended to only do calls to setenv()
  from an early phase of the program when no other threads have been started.