Event API

handle different aspects of the MqS event-queue More...

Typedefs
typedef void(*	MqEventF )(ContextSP)
	a prototype for a EventChecking procedure
typedef void(*	EventCreateF )(ContextSP)
	prototype for a EventQueueing procedure
Enumerations
enum	MqWaitOnEventE { MQ_WAIT = (1 << 0), MQ_FOREVER = (1 << 1) }
	wait for an event? More...
Functions
MQ_EXTERN MqErrorE	MqEventCheck (MqSP const msgque, const MqIoSelectE type, struct timeval *timeout, EventCreateF proc)
	check for a new event on all MqS objects currently defined.
MQ_EXTERN MqErrorE	MqProcessEvent (MqSP const msgque, const time_t timeout, const MqWaitOnEventE wait)
	waiting for an incoming packet on the single file-handle belonging to the MqS object.

---

Detailed Description

handle different aspects of the MqS event-queue

the event-queue have to be linked into an existing event-processing infrastructure. the linking is done by defining prototypes for two independent procedures:

• MqEventF is used to call an external event processing procedure (e.g. Tcl_DoOneEvent)
• EventCreateF is used to add events, created by the file-handles owned by the MqS objects, into the external event-queue (e.g. Tcl_QueueEvent)

---

Typedef Documentation

typedef void( * EventCreateF)(ContextSP)

prototype for a EventQueueing procedure Example: tclFreiburg 2.0 event-handling procedures void eventQueue(ContextSP const context) { MqEventS *event = (MqEventS*) ckalloc(sizeof(MqEventS)); event->header.proc = eventProcess; event->context = context; Tcl_QueueEvent((Tcl_Event*)event, TCL_QUEUE_TAIL); } void tclEventCheck(ClientData clientData, int flags) { if (!(flags & TCL_FILE_EVENTS)) return; struct timeval tv = {0L, 0L}; MqEventCheck(NULL, MQ_SELECT_RECV, &tv, eventQueue); } Definition at line 607 of file types.h.

---

Enumeration Type Documentation

enum MqWaitOnEventE

wait for an event? Enumeration values: MQ_WAIT  wait for new event MQ_FOREVER  wait forever Definition at line 262 of file types.h.

---

Function Documentation

MQ_EXTERN MqErrorE MqEventCheck (  MqSP const   msgque, const MqIoSelectE  type, struct timeval *  timeout, EventCreateF  proc )

check for a new event on all MqS objects currently defined. the checking is done by do a 'select' on all file-handles owned by the MqS objects and invoking the EventCreateF procedure to add new events into an external event-queue Change for 2.0: use an MqS object as first parameter Parameters: msgque  link to an MqS object type  specify the type of select (e.g. MQ_SELECT_RECV or MQ_SELECT_SEND) timeout  specify a timeout value in seconds proc  the procedure to add events into an external event-queue

MQ_EXTERN MqErrorE MqProcessEvent (  MqSP const   msgque, const time_t  timeout, const MqWaitOnEventE  wait )

waiting for an incoming packet on the single file-handle belonging to the MqS object. this procedure is used to wait for (e.g. MqWaitOnEventE == MQ_WAIT) or check (e.g. no MQ_WAIT) the file-handle for an incoming event. if an event occurs the header of the Msgque packet is parsed and the according service-handle is called. if MqWaitOnEventE == MQ_FOREVER the procedure will never return, accept for error processing. Example: tclFreiburg 2.0 event processing procedure static int eventProcess(Tcl_Event * evPtr, int flags) { if (!(flags & TCL_FILE_EVENTS)) return 0; MqSP const msgque = (((MqEventS*)evPtr)->context)->msgque; // check if event evPtr has disappeared until queuing 'eventQueue' MqErrorCheck(MqProcessEvent(msgque, MQ_TIMEOUT, !MQ_WAIT)); return 1; error: TclErrorGetResult (msgque); Tcl_BackgroundError (msgque->myCtx->interp); return 1; } Parameters: msgque  link to the MqS object timeout  a timeout value is seconds wait  some options for customization (e.g. MQ_WAIT or MQ_FOREVER)

---