X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=man%2Fsd_event_wait.xml;fp=man%2Fsd_event_wait.xml;h=4b7cf50b6dc635a1ae54073acf17c4dcb8dd058b;hb=42f1ab5009eed71f0d4f83681b8fdbed8664fca3;hp=0000000000000000000000000000000000000000;hpb=02d30981b1bef116caee26ef3229fb910a88a394;p=elogind.git diff --git a/man/sd_event_wait.xml b/man/sd_event_wait.xml new file mode 100644 index 000000000..4b7cf50b6 --- /dev/null +++ b/man/sd_event_wait.xml @@ -0,0 +1,213 @@ + + + + + + + + + sd_event_wait + systemd + + + + Developer + Tom + Gundersen + teg@jklm.no + + + + + + sd_event_wait + 3 + + + + sd_event_wait + sd_event_prepare + sd_event_dispatch + + Run parts of libsystemd event loop + + + + + #include <systemd/sd-event.h> + + + int sd_event_prepare + sd_event *event + + + + int sd_event_wait + sd_event *event + uint64_t timeout + + + + int sd_event_dispatch + sd_event *event + + + + + + + Description + + Functions described here form parts of an event loop. + + sd_event_prepare checks for pending + events and arms necessary timers. If any events are ready to be + processed, it returns a positive value, and the events should be + processed with sd_event_dispatch. + sd_event_dispatch runs a handler for one of + the events from the sources with the highest priority. On success, + sd_event_dispatch returns either 0, which + means that the loop is finished, or a positive value, which means + that the loop is again in the initial state and + sd_event_prepare should be called again. + + + In case sd_event_prepare returned 0, + sd_event_wait should be called to wait for + events or a timeout. If any events are ready to be processed, it + returns a positive value, and the events should be processed with + sd_event_dispatch. Otherwise, the loop is + back in the inital state and sd_event_prepare + should be called again. + + + ┌──────────┐ + │ initial ├──←←←←←←←←←←←←←←←←←←←─┐ + └───┬──────┘ ↑ + │ ↑ + sd_event_prepare ┌─────────┐ ↑ + ├ 0 →→→→→→→──┤ armed │ ↑ + 1 └───┬─────┘ ↑ + ↓ │ ↑ + ↓ sd_event_wait ↑ + ├───←←←←←←←─── 1 ┴─ 0 →→→→→→→─┘ + ┌───┴──────┐ ↑ + │ pending │ ↑ + └───┬──────┘ ↑ + │ ↑ + sd_event_dispatch ↑ + ↓ ↑ + ├ 1 ──────────→→→→→→→─────────┘ + 0 + ↓ + ┌───┴──────┐ + │ finished │ + └──────────┘ + + + All three functions as the first argument take the event + loop object event that is created with with + sd_event_new. The timeout for + sd_event_wait is specified with + timeout in milliseconds. + (uint64_t) -1 may be used to specify an + infinite timeout. + + + + Return Value + + On success, these functions return 0 or a positive integer. + On failure, they return a negative errno-style error code. In case + of sd_event_prepare and + sd_event_wait a positive value means that + events are ready to be processed and 0 means that no events are + ready. In case of sd_event_dispatch a + positive value means that the loop is again in the initial state + and 0 means the loop is finished. For any of those functions, a + negative return value means the loop must be aborted. + + + + Errors + + Returned errors may indicate the following problems: + + + + -EINVAL + + Parameter event is + NULL. + + + + -EBUSY + + The event loop object is not in the right + state. + + + + -ESTALE + + The event loop is already terminated. + + + + + -ECHILD + + The event loop has been created in a different process. + + + + + + Other errors are possible too. + + + + Notes + + Functions described here are available + as a shared library, which can be compiled and linked to with the + libsystemd pkg-config1 + file. + + + + See Also + + + systemd1, + sd_event_new3, + sd_event_run3, + sd_event_add_io3, + sd_event_add_time3, + sd_event_add_signal3, + sd_event_add_defer3, + sd_event_add_exit3, + sd_event_add_post3. + + + +