trusty (3) sd_booted.3.gz

NAME

       sd_booted - Test whether the system is running the systemd init system

SYNOPSIS

       #include <systemd/sd-daemon.h>

       int sd_booted(void);

DESCRIPTION

       sd_booted() checks whether the system was booted up using the systemd init system.

RETURN VALUE

       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.

NOTES

       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 directory /run/systemd/system/ exists. A simple check like
       this can also be implemented trivially in shell or any other language.

       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.c and sd-daemon.h files. These
       interfaces are available as shared library, which can be compiled and linked to with the
       libsystemd-daemonpkg-config(1) file. Alternatively, applications consuming these APIs may copy the
       implementation into their source tree. For more details about the reference implementation see sd-
       daemon(3).

       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.

SEE ALSO

       systemd(1), sd-daemon(3)