--- libevent-1.4.14b-stable/event.3 po lis 21 06:43:10 2011 +++ libevent-1.4.14b-stable/event.3 po lis 21 09:31:12 2011 @@ -26,527 +26,528 @@ .\" OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF .\" ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. .\" -.Dd August 8, 2000 -.Dt EVENT 3 -.Os -.Sh NAME -.Nm event_init , -.Nm event_dispatch , -.Nm event_loop , -.Nm event_loopexit , -.Nm event_loopbreak , -.Nm event_set , -.Nm event_base_dispatch , -.Nm event_base_loop , -.Nm event_base_loopexit , -.Nm event_base_loopbreak , -.Nm event_base_set , -.Nm event_base_free , -.Nm event_add , -.Nm event_del , -.Nm event_once , -.Nm event_base_once , -.Nm event_pending , -.Nm event_initialized , -.Nm event_priority_init , -.Nm event_priority_set , -.Nm evtimer_set , -.Nm evtimer_add , -.Nm evtimer_del , -.Nm evtimer_pending , -.Nm evtimer_initialized , -.Nm signal_set , -.Nm signal_add , -.Nm signal_del , -.Nm signal_pending , -.Nm signal_initialized , -.Nm bufferevent_new , -.Nm bufferevent_free , -.Nm bufferevent_write , -.Nm bufferevent_write_buffer , -.Nm bufferevent_read , -.Nm bufferevent_enable , -.Nm bufferevent_disable , -.Nm bufferevent_settimeout , -.Nm bufferevent_base_set , -.Nm evbuffer_new , -.Nm evbuffer_free , -.Nm evbuffer_add , -.Nm evbuffer_add_buffer , -.Nm evbuffer_add_printf , -.Nm evbuffer_add_vprintf , -.Nm evbuffer_drain , -.Nm evbuffer_write , -.Nm evbuffer_read , -.Nm evbuffer_find , -.Nm evbuffer_readline , -.Nm evhttp_new , -.Nm evhttp_bind_socket , -.Nm evhttp_free -.Nd execute a function when a specific event occurs -.Sh SYNOPSIS -.Fd #include -.Fd #include -.Ft "struct event_base *" -.Fn "event_init" "void" -.Ft int -.Fn "event_dispatch" "void" -.Ft int -.Fn "event_loop" "int flags" -.Ft int -.Fn "event_loopexit" "struct timeval *tv" -.Ft int -.Fn "event_loopbreak" "void" -.Ft void -.Fn "event_set" "struct event *ev" "int fd" "short event" "void (*fn)(int, short, void *)" "void *arg" -.Ft int -.Fn "event_base_dispatch" "struct event_base *base" -.Ft int -.Fn "event_base_loop" "struct event_base *base" "int flags" -.Ft int -.Fn "event_base_loopexit" "struct event_base *base" "struct timeval *tv" -.Ft int -.Fn "event_base_loopbreak" "struct event_base *base" -.Ft int -.Fn "event_base_set" "struct event_base *base" "struct event *" -.Ft void -.Fn "event_base_free" "struct event_base *base" -.Ft int -.Fn "event_add" "struct event *ev" "struct timeval *tv" -.Ft int -.Fn "event_del" "struct event *ev" -.Ft int -.Fn "event_once" "int fd" "short event" "void (*fn)(int, short, void *)" "void *arg" "struct timeval *tv" -.Ft int -.Fn "event_base_once" "struct event_base *base" "int fd" "short event" "void (*fn)(int, short, void *)" "void *arg" "struct timeval *tv" -.Ft int -.Fn "event_pending" "struct event *ev" "short event" "struct timeval *tv" -.Ft int -.Fn "event_initialized" "struct event *ev" -.Ft int -.Fn "event_priority_init" "int npriorities" -.Ft int -.Fn "event_priority_set" "struct event *ev" "int priority" -.Ft void -.Fn "evtimer_set" "struct event *ev" "void (*fn)(int, short, void *)" "void *arg" -.Ft void -.Fn "evtimer_add" "struct event *ev" "struct timeval *" -.Ft void -.Fn "evtimer_del" "struct event *ev" -.Ft int -.Fn "evtimer_pending" "struct event *ev" "struct timeval *tv" -.Ft int -.Fn "evtimer_initialized" "struct event *ev" -.Ft void -.Fn "signal_set" "struct event *ev" "int signal" "void (*fn)(int, short, void *)" "void *arg" -.Ft void -.Fn "signal_add" "struct event *ev" "struct timeval *" -.Ft void -.Fn "signal_del" "struct event *ev" -.Ft int -.Fn "signal_pending" "struct event *ev" "struct timeval *tv" -.Ft int -.Fn "signal_initialized" "struct event *ev" -.Ft "struct bufferevent *" -.Fn "bufferevent_new" "int fd" "evbuffercb readcb" "evbuffercb writecb" "everrorcb" "void *cbarg" -.Ft void -.Fn "bufferevent_free" "struct bufferevent *bufev" -.Ft int -.Fn "bufferevent_write" "struct bufferevent *bufev" "void *data" "size_t size" -.Ft int -.Fn "bufferevent_write_buffer" "struct bufferevent *bufev" "struct evbuffer *buf" -.Ft size_t -.Fn "bufferevent_read" "struct bufferevent *bufev" "void *data" "size_t size" -.Ft int -.Fn "bufferevent_enable" "struct bufferevent *bufev" "short event" -.Ft int -.Fn "bufferevent_disable" "struct bufferevent *bufev" "short event" -.Ft void -.Fn "bufferevent_settimeout" "struct bufferevent *bufev" "int timeout_read" "int timeout_write" -.Ft int -.Fn "bufferevent_base_set" "struct event_base *base" "struct bufferevent *bufev" -.Ft "struct evbuffer *" -.Fn "evbuffer_new" "void" -.Ft void -.Fn "evbuffer_free" "struct evbuffer *buf" -.Ft int -.Fn "evbuffer_add" "struct evbuffer *buf" "const void *data" "size_t size" -.Ft int -.Fn "evbuffer_add_buffer" "struct evbuffer *dst" "struct evbuffer *src" -.Ft int -.Fn "evbuffer_add_printf" "struct evbuffer *buf" "const char *fmt" "..." -.Ft int -.Fn "evbuffer_add_vprintf" "struct evbuffer *buf" "const char *fmt" "va_list ap" -.Ft void -.Fn "evbuffer_drain" "struct evbuffer *buf" "size_t size" -.Ft int -.Fn "evbuffer_write" "struct evbuffer *buf" "int fd" -.Ft int -.Fn "evbuffer_read" "struct evbuffer *buf" "int fd" "int size" -.Ft "u_char *" -.Fn "evbuffer_find" "struct evbuffer *buf" "const u_char *data" "size_t size" -.Ft "char *" -.Fn "evbuffer_readline" "struct evbuffer *buf" -.Ft "struct evhttp *" -.Fn "evhttp_new" "struct event_base *base" -.Ft int -.Fn "evhttp_bind_socket" "struct evhttp *http" "const char *address" "u_short port" -.Ft "void" -.Fn "evhttp_free" "struct evhttp *http" -.Ft int -.Fa (*event_sigcb)(void) ; -.Ft volatile sig_atomic_t -.Fa event_gotsig ; -.Sh DESCRIPTION +.TH EVENT 3 "21 November 2011" "libevent 1.4.14b" "libevent Manual" +.SH NAME +event_init, +event_dispatch, +event_loop, +event_loopexit, +event_loopbreak, +event_set, +event_base_dispatch, +event_base_loop, +event_base_loopexit, +event_base_loopbreak, +event_base_set, +event_base_free, +event_add, +event_del, +event_once, +event_base_once, +event_pending, +event_initialized, +event_priority_init, +event_priority_set, +evtimer_set, +evtimer_add, +evtimer_del, +evtimer_pending, +evtimer_initialized, +signal_set, +signal_add, +signal_del, +signal_pending, +signal_initialized, +bufferevent_new, +bufferevent_free, +bufferevent_write, +bufferevent_write_buffer, +bufferevent_read, +bufferevent_enable, +bufferevent_disable, +bufferevent_settimeout, +bufferevent_base_set, +evbuffer_new, +evbuffer_free, +evbuffer_add, +evbuffer_add_buffer, +evbuffer_add_printf, +evbuffer_add_vprintf, +evbuffer_drain, +evbuffer_write, +evbuffer_read, +evbuffer_find, +evbuffer_readline, +evhttp_new, +evhttp_bind_socket, +evhttp_free +\- execute a function when a specific event occurs +.SH LIBRARY +The libevent library (libevent, -levent) +.br +.SH SYNOPSIS +.LP +.nf +\fB#include \fP +\fB#include \fP + +\fBstruct event_base* \fBevent_init\fR\fR(\fBvoid\fP\fR); + +\fBint \fBevent_dispatch\fR\fR(\fBvoid\fP\fR); + +\fBint \fBevent_loop\fR\fR(\fBint \fIflags\fP\fR); + +\fBint \fBevent_loopexit\fR\fR(\fBstruct timeval* \fItv\fP\fR); + +\fBint \fBevent_loopbreak\fR\fR(\fBvoid\fP\fR); + +\fBvoid \fBevent_set\fR\fR(\fBstruct event* \fIev\fP\fR, \fBint \fIfd \fP\fR, \fBshort \fIevent\fP\fR, \fBvoid \fI(*fn)(\fBint, short, void *\fP\fR), \fBvoid* \fIarg\fP\fR); + +\fBint \fBevent_base_dispatch\fR\fR(\fBstruct event_base* \fIbase\fP\fR); + +\fBint \fBevent_base_loop\fR\fR(\fBstruct event_base* \fIbase\fP\fR, \fBint \fIflags\fP\fR); + +\fBint \fBevent_base_loopexit\fR\fR(\fBstruct event_base* \fIbase\fP\fR, \fBstruct timeval* \fItv\fP\fR); + +\fBint \fBevent_base_loopbreak\fR\fR(\fBstruct event_base* \fIbase\fP\fR); + +\fBint \fBevent_base_set\fR\fR(\fBstruct event_base* \fIbase\fP\fR, \fBstruct event* \fIev\fP\fR); + +\fBvoid \fBevent_base_free\fR\fR(\fBstruct event_base* \fIbase\fP\fR); + +\fBint \fBevent_add\fR\fR(\fBstruct event* \fIev\fP\fR, \fBstruct timeval* \fItv\fP\fR); + +.\fBint \fBevent_del\fR\fR(struct event* \fIev\fP\fR); + +\fBint \fBevent_once\fR\fR(\fBint \fIfd\fP\fR, \fBshort \fIevent\fP\fR, \fBvoid \fI(*fn)(\fBint, short, void*\fB\fR), \fBstruct timeval* \fItv\fP\fR); + +\fBint \fBevent_base_once\fR\fR(\fBstruct event_base* \fIbase\fP\fR, \fBint \fIfd\fB\fR, \fBshort \fIevent\fB\fR, \fBvoid \fI(*fn)(\fBint, short, void*\fB\fR), \fBvoid* \fIarg\fB\fR, \fBstruct timeval* \fItv\fP\fR); + +\fBint \fBevent_pending\fR\fR(\fBstruct event* \fIev\fP\fR, \fBshort \fIevent\fB\fR, \fBstruct timeval* \fItv\fP\fR); + +\fBint \fBevent_initialized\fR\fR(\fBstruct event* \fIev\fP\fR); + +\fBint \fBevent_priority_init\fR\fR (\fBint \fInpriorities\fP\fR); + +\fBint \fBevent_priority_set\fR\fR (\fBstruct event* \fIev\fP\fR, \fBint \fIpriority\fP\fR); + +\fBvoid \fBevtimer_set\fR\fR (\fBstruct event* \fIev\fP\fR, \fBvoid \fI(*fn)(\fBint, short, void*\fB\fR), \fBvoid* \fIarg\fP\fR); + +\fBvoid \fBevtimer_add\fR\fR (\fBstruct event* \fIev\fP\fR, \fBstruct timeval* \fItv\fP\fR); + +\fBvoid \fBevtimer_del\fR\fR (\fBstruct event* \fIev\fP\fR); + +\fBint \fBevtimer_pending\fR\fR (\fBstruct event* \fIev\fP\fR, \fBstruct timeval* \fItv\fP\fR); + +\fBint \fBevtimer_initialized\fR\fR(\fBstruct event* \fIev\fP\fR); + +\fBvoid \fBsignal_set\fR\fR (\fBstruct event* \fIev\fP\fR, \fBint \fIsignal\fP\fR, \fBvoid \fI(*fn)(\fBint, short, void*\fP\fR), \fBvoid* \fIarg\fP\fR); + +\fBvoid \fBsignal_add\fR\fR (\fBstruct event* \fIev\fP\fR, \fBstruct timeval* \fItv\fP\fR); + +\fBvoid \fBsignal_del\fR\fR (\fBstruct event* \fIev\fP\fR); + +\fBint \fBsignal_pending\fR\fR(\fBstruct event* \fIev\fP\fR, \fBstruct timeval* \fItv\fP\fR); + +\fBint \fBsignal_initialized\fR\fR(\fBstruct event* \fIev\fP\fR); + +\fBstruct bufferevent* \fBbufferevent_new\fR\fR(\fBint \fIfd\fP\fR, \fBevbuffercb \fIreadcb\fP\fR, \fBevbuffercb \fIwritecb\fP\fR, \fBeverrorcb \fIerrorcb\fP\fR, \fBvoid* \fIcbarg\fP\fR); + +\fBvoid \fBbufferevent_free\fR\fR(\fBstruct bufferevent* \fIbufev\fP\fR); + +\fBint \fBbufferevent_write\fR\fR(\fBstruct bufferevent* \fIbufev\fP\fR, \fBvoid* \fIdata\fP\fR, \fBsize_t \fIsize\fP\fR); + +\fBint \fBbufferevent_write_buffer\fR\fR(\fBstruct bufferevent* \fIbufev\fP\fR, \fBstruct evbuffer* \fIbuf\fP\fR); + +\fBsize_t \fBbufferevent_read\fR\fR(\fBstruct bufferevent* \fIbufev\fP\fR, \fBvoid* \fIdata\fP\fR, \fBsize_t \fIsize\fP\fR); + +\fBint \fBbufferevent_enable\fR\fR(\fBstruct bufferevent* \fIbufev\fP\fR, \fBshort \fIevent\fP\fR); + +\fBint \fBbufferevent_disable\fR\fR(\fBstruct bufferevent* \fIbufev\fP\fR, \fBshort \fIeven\fP\fR); + +\fBvoid \fBbufferevent_settimeout\fR\fR(\fBstruct bufferevent* \fIbufev\fP\fR, \fBint \fItimeout_read\fP\fR, \fBint \fItimeout_write\fP\fR); + +\fBint \fBbufferevent_base_set\fR\fR(\fBstruct event_base* \fIbase\fP\fR, \fBstruct bufferevent* \fIbufev\fP\fR); + +\fBstruct evbuffer* \fBevbuffer_new (\fBvoid\fP\fR); + +\fBvoid \fBevbuffer_free\fR\fR(\fBstruct evbuffer* \fIbuf\fP\fR); + +\fBint \fBevbuffer_add\fR\fR(\fBstruct evbuffer* \fIbuf\fP\fR, \fBconst void* \fIdata\fP\fR, \fBsize_t \fIsize\fP\fR); + +\fBint \fBevbuffer_add_buffer\fR\fR(\fBstruct evbuffer* \fIdst\fP\fR, \fBstruct evbuffer* \fIsrc\fP\fR); + +\fBint \fBevbuffer_add_printf\fR\fR(\fBstruct evbuffer* \fIbuf\fP\fR, \fBconst char* \fIfmt\fP\fR, \fB...\fP\fR); + +\fBint \fBevbuffer_add_vprintf\fR\fR(\fBstruct evbuffer* \fIbuf\fP\fR, \fBconst char* \fIfmt\fP\fR, \fBva_list \fIap\fP\fR); + +\fBvoid \fBevbuffer_drain\fR\fR(\fBstruct evbuffer* \fIbuf\fP\fR, \fBsize_t \fIsize\fP\fR); + +\fBint \fBevbuffer_write\fR\fR(\fBstruct evbuffer* \fIbuf\fP\fR, \fBint \fIfd\fP\fR); + +\fBint \fBevbuffer_read\fR\fR(\fBstruct evbuffer* \fIbuf\fP\fR, \fBint \fIfd\fP\fR, \fBint \fIsize\fP\fR); + +\fBu_char* \fBevbuffer_find\fR\fR(\fBstruct evbuffer* \fIbuf\fP\fR, \fBconst u_char* \fIdata\fP\fR, \fBsize_t \fIsize\fP\fR); + +\fBchar* \fBevbuffer_readline\fR\fR(\fBstruct evbuffer* \fIbuf\fP\fR); + +\fBstruct evhttp * \fBevhttp_new\fR\fR(\fBstruct event_base* \fIbase\fP\fR); + +\fBint \fBevhttp_bind_socket\fR\fR(\fBstruct evhttp* \fIhttp\fP\fR, \fBconst char* \fIaddress\fP\fR, \fBu_short \fIport\fP\fR); + +\fBvoid \fBevhttp_free\fR\fR(\fBstruct evhttp* \fIhttp\fP\fR); + +\fBint \fI(*event_sigcb)\fP\fR\fI(\fBvoid\fP\fR); + +\fBvolatile sig_atomic_t \fR\fRevent_gotsig\fP\fR; +.fi + +.SH DESCRIPTION The -.Nm event +\fIevent\fP\fR API provides a mechanism to execute a function when a specific event on a file descriptor occurs or after a given time has passed. -.Pp +.PP The -.Nm event +\fIevent\fP\fR API needs to be initialized with -.Fn event_init +\fBevent_init\fR before it can be used. -.Pp +.PP In order to process events, an application needs to call -.Fn event_dispatch . +\fBevent_dispatch\fP\fR. This function only returns on error, and should replace the event core of the application program. -.Pp +.PP The function -.Fn event_set +\fBevent_set\fP\fR prepares the event structure -.Fa ev +\fIev\fP\fR to be used in future calls to -.Fn event_add +\fBevent_add\fP\fR and -.Fn event_del . +\fBevent_del\fP\fR . The event will be prepared to call the function specified by the -.Fa fn +\fIfn\fP\fR argument with an -.Fa int +\fIint\fP\fR argument indicating the file descriptor, a -.Fa short +\fIshort\fP\fR argument indicating the type of event, and a -.Fa void * +\fIvoid*\fP\fR argument given in the -.Fa arg +\fIarg\fP\fR argument. The -.Fa fd +The \fIfd\fP\fR indicates the file descriptor that should be monitored for events. -The events can be either -.Va EV_READ , -.Va EV_WRITE , -or both, +The events can be either EV_READ, EV_WRITE , or both, indicating that an application can read or write from the file descriptor respectively without blocking. -.Pp +.PP The function -.Fa fn +\fIfn\fP\fR will be called with the file descriptor that triggered the event and the type of event which will be either -.Va EV_TIMEOUT , -.Va EV_SIGNAL , -.Va EV_READ , +EV_TIMEOUT, +EV_SIGNAL, +EV_READ, or -.Va EV_WRITE . +EV_WRITE. Additionally, an event which has registered interest in more than one of the preceeding events, via bitwise-OR to -.Fn event_set , +\fBevent_set\fP\fR, can provide its callback function with a bitwise-OR of more than one triggered event. The additional flag -.Va EV_PERSIST +EV_PERSIST makes an -.Fn event_add +\fBevent_add\fP\fR persistent until -.Fn event_del +\fBevent_del\fP\fR has been called. -.Pp +.PP Once initialized, the -.Fa ev +\fIev\fP\fR structure can be used repeatedly with -.Fn event_add +\fBevent_add\fP\fR and -.Fn event_del +\fBevent_del\fP\fR and does not need to be reinitialized unless the function called and/or the argument to it are to be changed. However, when an -.Fa ev +\fIev\fP\fR structure has been added to libevent using -.Fn event_add +\fBevent_add\fP\fR the structure must persist until the event occurs (assuming -.Fa EV_PERSIST +EV_PERSIST is not set) or is removed using -.Fn event_del . +\fBevent_del\fP\fR. You may not reuse the same -.Fa ev +\fIev\fP\fR structure for multiple monitored descriptors; each descriptor needs its own -.Fa ev . -.Pp +\fIev\fP\fR. +.PP The function -.Fn event_add +\fBevent_add\fP\fR schedules the execution of the -.Fa ev +\fIev\fP\fR event when the event specified in -.Fn event_set +\fBevent_set\fP\fR occurs or in at least the time specified in the -.Fa tv . +\fItv\fP\fR If -.Fa tv +\fItv\fP\fR is -.Dv NULL , +\fINULL\fP\fR, no timeout occurs and the function will only be called if a matching event occurs on the file descriptor. The event in the -.Fa ev +\fIev\fP\fR argument must be already initialized by -.Fn event_set +\fBevent_set\fP\fR and may not be used in calls to -.Fn event_set +\fBevent_set\fP\fR until it has timed out or been removed with -.Fn event_del . +\fBevent_del\fP\fR. If the event in the -.Fa ev +\fIev\fP\fR argument already has a scheduled timeout, the old timeout will be replaced by the new one. -.Pp +.PP The function -.Fn event_del +\fBevent_del\fP\fR will cancel the event in the argument -.Fa ev . +\fIev\fP\fR. If the event has already executed or has never been added the call will have no effect. -.Pp +.PP The functions -.Fn evtimer_set , -.Fn evtimer_add , -.Fn evtimer_del , -.Fn evtimer_initialized , +\fBevtimer_set\fP\fR, +\fBevtimer_add\fP\fR, +\fBevtimer_del\fP\fR, +\fBevtimer_initialized\fP\fR, and -.Fn evtimer_pending +\fBevtimer_pending\fP\fR are abbreviations for common situations where only a timeout is required. The file descriptor passed will be \-1, and the event type will be -.Va EV_TIMEOUT . -.Pp +EV_TIMEOUT. +.PP The functions -.Fn signal_set , -.Fn signal_add , -.Fn signal_del , -.Fn signal_initialized , +\fBsignal_set\fP\fR, +\fBsignal_add\fP\fR, +\fBsignal_del\fP\fR, +\fBsignal_initialized\fP\fR, and -.Fn signal_pending +\fBsignal_pending\fP\fR are abbreviations. The event type will be a persistent -.Va EV_SIGNAL . +EV_SIGNAL . That means -.Fn signal_set +\fBsignal_set\fP\fR adds -.Va EV_PERSIST . -.Pp +EV_PERSIST. +.PP In order to avoid races in signal handlers, the -.Nm event +\fIevent\fP\fR API provides two variables: -.Va event_sigcb +\fBevent_sigcb\fP\fR and -.Va event_gotsig . +\fBevent_gotsig\fP\fR. A signal handler sets -.Va event_gotsig +\fBevent_gotsig\fP\fR to indicate that a signal has been received. The application sets -.Va event_sigcb +\fBevent_sigcb\fP\fR to a callback function. After the signal handler sets -.Va event_gotsig , -.Nm event_dispatch +\fBevent_gotsig\fP\fR, +\fBevent_dispatch()\fP\fR will execute the callback function to process received signals. The callback returns 1 when no events are registered any more. It can return \-1 to indicate an error to the -.Nm event +\fIevent\fP\fR library, causing -.Fn event_dispatch +\fBevent_dispatch\fP\fR to terminate with -.Va errno +\fBerrno\fP\fR set to -.Er EINTR . -.Pp +\fBEINTR\fP\fR. +.PP The function -.Fn event_once +\fBevent_once\fP\fR is similar to -.Fn event_set . +\fBevent_set\fP\fR. However, it schedules a callback to be called exactly once and does not require the caller to prepare an -.Fa event +\fIevent\fP\fR structure. This function supports -.Fa EV_TIMEOUT , -.Fa EV_READ , +EV_TIMEOUT, +EV_READ, and -.Fa EV_WRITE . -.Pp +EV_WRITE. +.PP The .Fn event_pending +\fBevent_pending\fP\fR function can be used to check if the event specified by -.Fa event +\fIevent\fP\fR is pending to run. If -.Va EV_TIMEOUT +EV_TIMEOUT was specified and -.Fa tv +\fItv\fP\fR is not -.Dv NULL , +\fINULL\fP\fR, the expiration time of the event will be returned in -.Fa tv . -.Pp +\fItv\fP\fR. +.PP The -.Fn event_initialized +\fBevent_initialized\fP\fR macro can be used to check if an event has been initialized. -.Pp +.PP The -.Nm event_loop +\fBevent_loop\fP\fR function provides an interface for single pass execution of pending events. The flags -.Va EVLOOP_ONCE +EVLOOP_ONCE and -.Va EVLOOP_NONBLOCK +EVLOOP_NONBLOCK are recognized. The -.Nm event_loopexit +\fBevent_loopexit\fP\fR function exits from the event loop. The next -.Fn event_loop +\fBevent_loop\fP\fR iteration after the given timer expires will complete normally (handling all queued events) then exit without blocking for events again. Subsequent invocations of -.Fn event_loop +\fBevent_loop\fP\fR will proceed normally. The -.Nm event_loopbreak +\fBevent_loopbreak\fP\fR function exits from the event loop immediately. -.Fn event_loop +\fBevent_loop\fP\fR will abort after the next event is completed; -.Fn event_loopbreak +\fBevent_loopbreak\fP\fR is typically invoked from this event's callback. This behavior is analogous to the "break;" statement. Subsequent invocations of -.Fn event_loop +\fBevent_loop\fP\fR will proceed normally. -.Pp +.PP It is the responsibility of the caller to provide these functions with pre-allocated event structures. -.Pp -.Sh EVENT PRIORITIES +.PP +.SH EVENT PRIORITIES By default -.Nm libevent +\fIlibevent\fP\fR schedules all active events with the same priority. However, sometimes it is desirable to process some events with a higher priority than others. For that reason, -.Nm libevent +\fIlibevent\fP\fR supports strict priority queues. Active events with a lower priority are always processed before events with a higher priority. -.Pp +.PP The number of different priorities can be set initially with the -.Fn event_priority_init +\fBevent_priority_init\fP\fR function. This function should be called before the first call to -.Fn event_dispatch . +\fBevent_dispatch\fP\fR. The -.Fn event_priority_set +\fBevent_priority_set\fP\fR function can be used to assign a priority to an event. By default, -.Nm libevent +\fIlibevent\fP\fR assigns the middle priority to all events unless their priority is explicitly set. -.Sh THREAD SAFE EVENTS -.Nm Libevent +.SH THREAD SAFE EVENTS +\fIlibevent\fP\fR has experimental support for thread-safe events. When initializing the library via .Fn event_init , an event base is returned. This event base can be used in conjunction with calls to -.Fn event_base_set , -.Fn event_base_dispatch , -.Fn event_base_loop , -.Fn event_base_loopexit , -.Fn bufferevent_base_set +\fBevent_base_set()\fP\fR, +\fBevent_base_dispatch()\fP\fR, +\fBevent_base_loop()\fP\fR, +\fBevent_base_loopexit()\fP\fR, +\fBbufferevent_base_set()\fP\fR and -.Fn event_base_free . -.Fn event_base_set +\fBevent_base_free()\fP\fR. +\fBevent_base_set()\fP\fR should be called after preparing an event with -.Fn event_set , +\fBevent_set()\fP\fR, as -.Fn event_set +\fBevent_set()\fP\fR, assigns the provided event to the most recently created event base. -.Fn bufferevent_base_set +\fBbufferevent_base_set()\fP\fR should be called after preparing a bufferevent with -.Fn bufferevent_new . -.Fn event_base_free +\fBbufferevent_new()\fP\fR. +\fBevent_base_free()\fP\fR should be used to free memory associated with the event base when it is no longer needed. -.Sh BUFFERED EVENTS -.Nm libevent +.SH BUFFERED EVENTS +\fIlibevent\fP\fR provides an abstraction on top of the regular event callbacks. This abstraction is called a -.Va "buffered event" . +\fB"buffered event"\fP\fR. A buffered event provides input and output buffers that get filled and drained automatically. The user of a buffered event no longer deals directly with the IO, but instead is reading from input and writing to output buffers. -.Pp +.PP A new bufferevent is created by -.Fn bufferevent_new . +\fBbufferevent_new()\fP\fR. The parameter -.Fa fd +\fIfd\fP\fR specifies the file descriptor from which data is read and written to. This file descriptor is not allowed to be a -.Xr pipe 2 . +\fBpipe(2)\fR. The next three parameters are callbacks. The read and write callback have the following form: -.Ft void -.Fn "(*cb)" "struct bufferevent *bufev" "void *arg" . +\fBvoid \fB(*cb)\fR\fR(\fBstruct bufferevent* \fIbufev\fP\fR, \fBvoid* \fIarg\fP\fR). The error callback has the following form: -.Ft void -.Fn "(*cb)" "struct bufferevent *bufev" "short what" "void *arg" . +\fBvoid \fB(*cb)\fR\fR(\fBstruct bufferevent* \fIbufev\fP\fR, \fBshort \fIwhat\fP\fR, \fBvoid* \fIarg\fP\fR). The argument is specified by the fourth parameter -.Fa "cbarg" . +\fBcbarg\fP\fR. A -.Fa bufferevent struct -pointer is returned on success, NULL on error. -Both the read and the write callback may be NULL. +\fBstruct bufferevent\fP\fR +pointer is returned on success, \fINULL\fP\fR on error. +Both the read and the write callback may be \fINULL\fP\fR. The error callback has to be always provided. -.Pp +.PP Once initialized, the bufferevent structure can be used repeatedly with bufferevent_enable() and bufferevent_disable(). The flags parameter can be a combination of -.Va EV_READ +EV_READ and -.Va EV_WRITE . +EV_WRITE . When read enabled the bufferevent will try to read from the file descriptor and call the read callback. The write callback is executed whenever the output buffer is drained below the write low watermark, which is -.Va 0 +\fI0\fP\fR by default. -.Pp +.PP The -.Fn bufferevent_write +\fBbufferevent_write()\fP\fR function can be used to write data to the file descriptor. The data is appended to the output buffer and written to the descriptor automatically as it becomes available for writing. -.Fn bufferevent_write +\fBbufferevent_write()\fP\fR returns 0 on success or \-1 on failure. The -.Fn bufferevent_read +\fBbufferevent_read()\fP\fR function is used to read data from the input buffer, returning the amount of data read. -.Pp +.PP If multiple bases are in use, bufferevent_base_set() must be called before enabling the bufferevent for the first time. .Sh NON-BLOCKING HTTP SUPPORT @@ -549,74 +550,74 @@ .Pp If multiple bases are in use, bufferevent_base_set() must be called before enabling the bufferevent for the first time. -.Sh NON-BLOCKING HTTP SUPPORT -.Nm libevent +.SH NON-BLOCKING HTTP SUPPORT +\fIlibevent\fP\fR provides a very thin HTTP layer that can be used both to host an HTTP server and also to make HTTP requests. An HTTP server can be created by calling -.Fn evhttp_new . +\fBevhttp_new\fP\fR. It can be bound to any port and address with the -.Fn evhttp_bind_socket +\fBevhttp_bind_socket\fP\fR function. When the HTTP server is no longer used, it can be freed via -.Fn evhttp_free . -.Pp +\fBevhttp_free\fP\fR. +.PP To be notified of HTTP requests, a user needs to register callbacks with the HTTP server. This can be done by calling -.Fn evhttp_set_cb . +\fBevhttp_set_cb\fP\fR. The second argument is the URI for which a callback is being registered. The corresponding callback will receive an -.Va struct evhttp_request +\fIstruct evhttp_request\fP\fR object that contains all information about the request. -.Pp +.PP This section does not document all the possible function calls; please check -.Va event.h +\fBevent.h\fP\fR for the public interfaces. -.Sh ADDITIONAL NOTES +.SH ADDITIONAL NOTES It is possible to disable support for -.Va epoll , kqueue , devpoll , poll +\fBepoll , kqueue , devpoll , poll\fP\fR or -.Va select +\fBselect\fP\fR by setting the environment variable -.Va EVENT_NOEPOLL , EVENT_NOKQUEUE , EVENT_NODEVPOLL , EVENT_NOPOLL +EVENT_NOEPOLL, EVENT_NOKQUEUE, EVENT_NODEVPOLL, EVENT_NOPOLL or -.Va EVENT_NOSELECT , +EVENT_NOSELECT, respectively. By setting the environment variable -.Va EVENT_SHOW_METHOD , -.Nm libevent +EVENT_SHOW_METHOD, +\fIlibevent\fP\fR displays the kernel notification method that it uses. -.Sh RETURN VALUES +.SH RETURN VALUES Upon successful completion -.Fn event_add +\fBevent_add\fP\fR and -.Fn event_del +\fBevent_del\fP\fR return 0. Otherwise, \-1 is returned and the global variable errno is set to indicate the error. -.Sh SEE ALSO -.Xr kqueue 2 , -.Xr poll 2 , -.Xr select 2 , -.Xr evdns 3 , -.Xr timeout 9 -.Sh HISTORY +.SH SEE ALSO +\fBpoll(2)\fR, +\fBselect(3C)\fR, +\fBport_create(3C)\fR, +\fBevdns(3)\fR, +\fBtimeout(9f)\fR. +.SH HISTORY The -.Nm event +\fIevent\fP\fR API manpage is based on the -.Xr timeout 9 +\fBtimeout(9)\fR manpage by Artur Grabowski. The port of -.Nm libevent +\fBlibevent\fP\fR to Windows is due to Michael A. Davis. Support for real-time signals is due to Taral. -.Sh AUTHORS +.SH AUTHORS The -.Nm event +\fIevent\fP\fR library was written by Niels Provos. -.Sh BUGS +.SH BUGS This documentation is neither complete nor authoritative. If you are in doubt about the usage of this API then check the source code to find out how it works, write