Minimal sytemd app

CMakeLists.txt

cmake_minimum_required(VERSION 3.6)
project(testd)

set(CMAKE_CXX_STANDARD 11)

find_package(PkgConfig)

pkg_check_modules(SYSTEMD libsystemd REQUIRED)
IF(NOT SYSTEMD_FOUND)
    message(FATAL_ERROR "ERROR: Systemd not found")
ENDIF(NOT SYSTEMD_FOUND)

set(SOURCE_FILES main.cpp)
add_executable(testd ${SOURCE_FILES})
target_link_libraries(testd ${SYSTEMD_LIBRARIES})

gistfile1.txt

* create test service in /etc/systemd/system
* activate service with sudo systemctl enable /etc/systemd/system/test.service
* start service with sudo systemctl start test.service
* debug journalctl -f -u test.service

main.cpp

#include <iostream>
#include <systemd/sd-journal.h>

int main() {
    std::cout << "Hello, World!" << std::endl;
    sd_journal_print(LOG_NOTICE, "Hello, world");
    return 0;
}

test.service

[Unit]
Description=A simple test

[Service]
ExecStart=/home/foo/bin/testd

[Install]
WantedBy=multi-user.target