From dc83f27a7cf03757dec11a69ec18504ad4ea8f89 Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Thu, 19 Nov 2015 23:38:54 +0100 Subject: man: fully document sd-event interfaces This completes the set of man pages for sd-event and contains some minor other fixes for other man pages too. The sd_event_set_name(3) man page is renamed to sd_event_source_set_description(3), which is the correct name of the concept today. --- man/sd_event_add_signal.xml | 118 +++++++++++++++++++++++++++----------------- 1 file changed, 73 insertions(+), 45 deletions(-) (limited to 'man/sd_event_add_signal.xml') diff --git a/man/sd_event_add_signal.xml b/man/sd_event_add_signal.xml index 0923fe0ae7..b5312735d2 100644 --- a/man/sd_event_add_signal.xml +++ b/man/sd_event_add_signal.xml @@ -21,7 +21,7 @@ along with systemd; If not, see . --> - + sd_event_add_signal @@ -45,13 +45,24 @@ sd_event_add_signal sd_event_source_get_signal + sd_event_signal_handler_t - Add a signal event source to an event loop + Add a UNIX process signal event source to an event + loop - #include <systemd/sd-bus.h> + #include <systemd/sd-event.h> + + typedef struct sd_event_source sd_event_source; + + + typedef int (*sd_event_signal_handler_t) + sd_event_source *s + const struct signalfd_siginfo *si + void *userdata + int sd_event_add_signal @@ -62,13 +73,6 @@ void *userdata - - typedef int (*sd_event_signal_handler_t) - sd_event_source *s - const struct signalfd_siginfo *si - void *userdata - - int sd_event_source_get_signal sd_event_source *source @@ -80,41 +84,61 @@ Description - sd_event_add_signal() adds a new signal - event source to an event loop object. The event loop is specified - in event, and the event source is returned in - the source parameter. The - signal parameter specifies the signal to be handled - (see - signal7). - The handler must reference a function to - call when the signal is delivered or be NULL. - The handler function will be passed the - userdata pointer, which may be chosen + sd_event_add_signal() adds a new UNIX + process signal event source to an event loop. The event loop + object is specified in the event parameter, + and the event source object is returned in the + source parameter. The + signal parameter specifies the numeric + signal to be handled (see signal7). + The handler parameter must reference a + function to call when the signal is received or be + NULL. The handler function will be passed + the userdata pointer, which may be chosen freely by the caller. The handler also receives a pointer to a - const struct signalfd_siginfo containing - the information about the received signal. See - signalfd2 + signalfd_siginfo structure containing + information about the received signal. See signalfd2 for further information. Only a single handler may be installed for a specific - signal. The signal will be unblocked, and must be - blocked when the function is called. If the handler is not - specified (handler is + signal. The signal will be unblocked by this call, and must be + blocked before this function is called in all threads (using + sigprocmask2). If + the handler is not specified (handler is NULL), a default handler which causes the - program to exit will be used. By default, the handler is enabled - permanently (SD_EVENT_ON), but this may be - changed with + program to exit cleanly will be used. + + By default, the event source is enabled permanently + (SD_EVENT_ON), but this may be changed with sd_event_source_set_enabled3. If the handler function returns a negative error code, it will be - disabled after the invocation, even if - SD_EVENT_ON mode is set. + disabled after the invocation, even if the + SD_EVENT_ON mode was requested before. + To destroy an event source object use + sd_event_source_unref3, + but note that the event source is only removed from the event loop + when all references to the event source are dropped. To make sure + an event source does not fire anymore, even when there's still a + reference to it kept, consider setting the event source to + SD_EVENT_OFF with + sd_event_source_set_enabled3. + + If the the second parameter of + sd_event_add_signal() is passed as NULL no + reference to the event source object is returned. In this case the + event source is considered "floating", and will be destroyed + implicitly when the event loop itself is destroyed. + sd_event_source_get_signal() retrieves - the configured signal number of a signal event source created - previously with sd_event_add_signal(). It - takes the event source object as the source + the configured UNIX process signal number of a signal event source + created previously with + sd_event_add_signal(). It takes the event + source object as the source parameter. @@ -168,19 +192,17 @@ - - + + -EDOM - - Notes + The passed event source is not a signal event source. + - sd_event_add_signal() and the other functions - described here are available as a shared library, which can be - compiled and linked to with the - libsystemd pkg-config1 - file. + + + See Also @@ -188,10 +210,16 @@ systemd1, sd-event3, sd_event_new3, + sd_event_now3, + sd_event_add_io3, sd_event_add_time3, sd_event_add_child3, sd_event_add_defer3, - sd_event_source_set_enabled3 + sd_event_source_set_enabled3, + sd_event_source_set_description3, + sd_event_source_set_userdata3, + signal7, + signalfd2 -- cgit v1.2.3-54-g00ecf