sd_event_source_set_description(3) — Linux manual page


SD_EVE...RIPTION(3)  sd_event_source_set_description SD_EVE...RIPTION(3)

NAME         top

       sd_event_source_set_description, sd_event_source_get_description
       - Set or retrieve descriptive names of event sources

SYNOPSIS         top

       #include <systemd/sd-event.h>

       int sd_event_source_set_description(sd_event_source *source,
                                           const char *description);

       int sd_event_source_get_description(sd_event_source *source,
                                           const char **description);

DESCRIPTION         top

       sd_event_source_set_description() may be used to set an arbitrary
       descriptive name for the event source object specified as source.
       This name will be used in debugging messages generated by
       sd-event(3) for this event source, and may be queried using
       sd_event_source_get_description() for debugging purposes. The
       description parameter shall point to a NUL-terminated string or
       be NULL. In the latter case, the descriptive name will be unset.
       The string is copied internally, hence the description argument
       is not referenced after the function returns.

       sd_event_source_get_description() may be used to query the
       current descriptive name assigned to the event source object
       source. It returns a pointer to the current name in description,
       stored in memory internal to the event source. The memory is
       invalidated when the event source is destroyed or the descriptive
       name is changed.

       Event source objects generally have no description set when they
       are created, except for UNIX signal event sources created with
       sd_event_add_signal(3), whose descriptive name is initialized to
       the signal's C constant name (e.g.  "SIGINT" or "SIGTERM").

RETURN VALUE         top

       On success, sd_event_source_set_description() and
       sd_event_source_get_description() return a non-negative integer.
       On failure, they return a negative errno-style error code.

       Returned errors may indicate the following problems:

           source is not a valid pointer to an sd_event_source object or
           the description argument for
           sd_event_source_get_description() is NULL.

           Not enough memory to copy the name.

           The event loop has been created in a different process,
           library or module instance.

           No name was set for the event source.

NOTES         top

       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

HISTORY         top

       sd_event_source_set_description() and
       sd_event_source_get_description() were added in version 229.

SEE ALSO         top

       sd-event(3), sd_event_add_io(3), sd_event_add_time(3),
       sd_event_add_signal(3), sd_event_add_child(3),
       sd_event_add_inotify(3), sd_event_add_defer(3),

COLOPHON         top

       This page is part of the systemd (systemd system and service
       manager) project.  Information about the project can be found at
       ⟨⟩.  If you have
       a bug report for this manual page, see
       This page was obtained from the project's upstream Git repository
       ⟨⟩ on 2023-12-22.  (At that
       time, the date of the most recent commit that was found in the
       repository was 2023-12-22.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to

systemd 255                                          SD_EVE...RIPTION(3)

Pages that refer to this page: sd-event(3)sd_event_add_child(3)sd_event_add_defer(3)sd_event_add_inotify(3)sd_event_add_io(3)sd_event_add_memory_pressure(3)sd_event_add_signal(3)sd_event_add_time(3)sd_event_source_set_floating(3)sd_event_source_set_userdata(3)systemd.directives(7)systemd.index(7)