SD_EVENT_SOURCE_UNREF(3) sd_event_source_unref SD_EVENT_SOURCE_UNREF(3)
sd_event_source_unref, sd_event_source_unrefp, sd_event_source_ref, sd_event_source_disable_unref, sd_event_source_disable_unrefp - Increase or decrease event source reference counters
#include <systemd/sd-event.h> sd_event_source* sd_event_source_unref(sd_event_source *source); void sd_event_source_unrefp(sd_event_source **source); sd_event_source* sd_event_source_ref(sd_event_source *source); sd_event_source* sd_event_source_disable_unref(sd_event_source *source); void sd_event_source_disable_unrefp(sd_event_source **source);
sd_event_source_unref() may be used to decrement by one the reference counter of the event source object specified as source. The reference counter is initially set to one, when the event source is created with calls such as sd_event_add_io(3) or sd_event_add_time(3). When the reference counter reaches zero it is removed from its event loop object and destroyed. sd_event_source_unrefp() is similar to sd_event_source_unref() but takes a pointer to a pointer to an sd_event_source object. This call is useful in conjunction with GCC's and LLVM's Clean-up Variable Attribute. Note that this function is defined as inline function. sd_event_source_ref() may be used to increase by one the reference counter of the event source object specified as source. sd_event_source_unref(), sd_bus_creds_unrefp() and sd_bus_creds_ref() execute no operation if the passed event source object is NULL. Note that event source objects stay alive and may be dispatched as long as they have a reference counter greater than zero. In order to drop a reference of an event source and make sure the associated event source handler function is not called anymore it is recommended to combine a call of sd_event_source_unref() with a prior call to sd_event_source_set_enabled() with SD_EVENT_OFF or call sd_event_source_disable_unref(), see below. sd_event_source_disable_unref() combines a call to sd_event_source_set_enabled() with SD_EVENT_OFF with sd_event_source_unref(). This ensures that the source is disabled before the local reference to it is lost. The source parameter is allowed to be NULL. sd_event_source_disable_unrefp() is similar to sd_event_source_unrefp(), but in addition disables the source first. This call is useful in conjunction with GCC's and LLVM's Clean-up Variable Attribute. Note that this function is defined as inline function.
sd_event_source_unref() and sd_event_source_disable_unref() always return NULL. sd_event_source_ref() always returns the event source object passed in.
These APIs are implemented as a shared library, which can be compiled and linked to with the libsystemd pkg-config(1) file.
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), sd_event_source_set_enabled(3)
1. Clean-up Variable Attribute https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html
This page is part of the systemd (systemd system and service manager) project. Information about the project can be found at ⟨http://www.freedesktop.org/wiki/Software/systemd⟩. If you have a bug report for this manual page, see ⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩. This page was obtained from the project's upstream Git repository ⟨https://github.com/systemd/systemd.git⟩ on 2020-08-13. (At that time, the date of the most recent commit that was found in the repos‐ itory was 2020-08-11.) 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 email@example.com systemd 246 SD_EVENT_SOURCE_UNREF(3)
Pages that refer to this page: 30-systemd-environment-d-generator(7), systemd.index(7)