sd_booted — Test whether the system is running the systemd init system
sd_booted() checks whether
the system was booted up using the systemd init system.
On failure, this call returns a negative errno-style error code. If the system was booted up with systemd as init system, this call returns a positive return value, zero otherwise.
This function is provided by the reference implementation of APIs for new-style daemons and distributed with the systemd package. The algorithm it implements is simple, and can easily be reimplemented in daemons if it is important to support this interface without using the reference implementation.
Internally, this function checks whether the
exists. A simple check like this can also be
implemented trivially in shell or any other
For details about the algorithm check the liberally licensed reference implementation sources: http://cgit.freedesktop.org/systemd/systemd/plain/src/libsystemd-daemon/sd-daemon.c and http://cgit.freedesktop.org/systemd/systemd/plain/src/systemd/sd-daemon.h
sd_booted() is implemented
in the reference implementation's
sd-daemon.h files. These
interfaces are available as shared library, which can
be compiled and linked to with the
file. Alternatively, applications consuming these APIs
may copy the implementation into their source
tree. For more details about the reference
If the reference implementation is used as drop-in files and -DDISABLE_SYSTEMD is set during compilation, this function will always return 0 and otherwise become a NOP.