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Diffstat (limited to 'doc/Notifier.3')
| -rw-r--r-- | doc/Notifier.3 | 131 |
1 files changed, 91 insertions, 40 deletions
diff --git a/doc/Notifier.3 b/doc/Notifier.3 index fd1adfd..a6c9280 100644 --- a/doc/Notifier.3 +++ b/doc/Notifier.3 @@ -1,47 +1,59 @@ '\" +'\" Copyright (c) 1998-1999 Scriptics Corporation '\" Copyright (c) 1995-1997 Sun Microsystems, Inc. '\" '\" See the file "license.terms" for information on usage and redistribution '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. '\" -'\" RCS: @(#) $Id: Notifier.3,v 1.4 1999/04/21 21:50:22 rjohnson Exp $ +'\" RCS: @(#) $Id: Notifier.3,v 1.5 1999/04/30 22:45:00 stanton Exp $ '\" .so man.macros -.TH Notifier 3 8.0 Tcl "Tcl Library Procedures" +.TH Notifier 3 8.1 Tcl "Tcl Library Procedures" .BS -.VS .SH NAME -Tcl_CreateEventSource, Tcl_DeleteEventSource, Tcl_SetMaxBlockTime, Tcl_QueueEvent, Tcl_DeleteEvents, Tcl_WaitForEvent, Tcl_SetTimer, Tcl_ServiceAll, Tcl_ServiceEvent, Tcl_GetServiceMode, Tcl_SetServiceMode \- the event queue and notifier interfaces - +Tcl_CreateEventSource, Tcl_DeleteEventSource, Tcl_SetMaxBlockTime, Tcl_QueueEvent, Tcl_ThreadQueueEvent, Tcl_ThreadAlert, Tcl_GetCurrentThread, Tcl_DeleteEvents, Tcl_InitNotifier, Tcl_FinalizeNotifier, Tcl_WaitForEvent, Tcl_AlertNotifier, Tcl_SetTimer, Tcl_ServiceAll, Tcl_ServiceEvent, Tcl_GetServiceMode, Tcl_SetServiceMode \- the event queue and notifier interfaces .SH SYNOPSIS .nf \fB#include <tcl.h>\fR .sp -\fBTcl_CreateEventSource\fR(\fIsetupProc, checkProc, clientData\fB)\fR +void +\fBTcl_CreateEventSource\fR(\fIsetupProc, checkProc, clientData\fR) .sp -\fBTcl_DeleteEventSource\fR(\fIsetupProc, checkProc, clientData\fB)\fR +void +\fBTcl_DeleteEventSource\fR(\fIsetupProc, checkProc, clientData\fR) .sp -\fBTcl_SetMaxBlockTime\fR(\fItimePtr\fB)\fR +void +\fBTcl_SetMaxBlockTime\fR(\fItimePtr\fR) .sp +void \fBTcl_QueueEvent\fR(\fIevPtr, position\fR) +.VS 8.1 .sp +void \fBTcl_ThreadQueueEvent\fR(\fIthreadId, evPtr, position\fR) -.VS .sp -\fBTcl_DeleteEvents\fR(\fIdeleteProc, clientData\fR) +void +\fBTcl_ThreadAlert\fR(\fIthreadId, clientData\fR) .sp -int -\fBTcl_WaitForEvent\fR(\fItimePtr\fR) +Tcl_ThreadId +\fBTcl_GetCurrentThread\fR() +.sp +void +\fBTcl_DeleteEvents\fR(\fIdeleteProc, clientData\fR) .sp ClientData \fBTcl_InitNotifier\fR() .sp +void \fBTcl_FinalizeNotifier\fR(\fIclientData\fR) .sp -\fBTcl_AlertNotifier\fR(\fIclientData\fR) +int +\fBTcl_WaitForEvent\fR(\fItimePtr\fR) .sp -\fBTcl_ThreadAlert\fR(\fIthreadId\fR) +void +\fBTcl_AlertNotifier\fR(\fIclientData\fR) .sp +void \fBTcl_SetTimer\fR(\fItimePtr\fR) .sp int @@ -59,7 +71,6 @@ int .SH ARGUMENTS .AS Tcl_EventDeleteProc milliseconds -.AS Tcl_EventSetupProc *setupProc .AP Tcl_EventSetupProc *setupProc in Procedure to invoke to prepare for event wait in \fBTcl_DoOneEvent\fR. .AP Tcl_EventCheckProc *checkProc in @@ -81,12 +92,14 @@ have been allocated by the caller using \fBTcl_Alloc\fR or \fBckalloc\fR. .AP Tcl_QueuePosition position in Where to add the new event in the queue: \fBTCL_QUEUE_TAIL\fR, \fBTCL_QUEUE_HEAD\fR, or \fBTCL_QUEUE_MARK\fR. +.AP Tcl_ThreadId threadId in +A unique identifier for a thread. +.AP Tcl_EventDeleteProc *deleteProc in +Procedure to invoke for each queued event in \fBTcl_DeleteEvents\fR. .AP int flags in What types of events to service. These flags are the same as those passed to \fBTcl_DoOneEvent\fR. -.AP Tcl_EventDeleteProc *deleteProc in -Procedure to invoke for each queued event in \fBTcl_DeleteEvents\fR. -.VS +.VS 8.1 .AP int mode in Inidicates whether events should be serviced by \fBTcl_ServiceAll\fR. Must be one of \fBTCL_SERVICE_NONE\fR or \fBTCL_SERVICE_ALL\fR. @@ -95,13 +108,11 @@ Must be one of \fBTCL_SERVICE_NONE\fR or \fBTCL_SERVICE_ALL\fR. .SH INTRODUCTION .PP -.VS The interfaces described here are used to customize the Tcl event loop. The two most common customizations are to add new sources of events and to merge Tcl's event loop with some other event loop, such as one provided by an application in which Tcl is embedded. Each of these tasks is described in a separate section below. -.VE .PP The procedures in this manual entry are the building blocks out of which the Tcl event notifier is constructed. The event notifier is the lowest @@ -119,20 +130,24 @@ higher-level software that they have occurred. The procedures and \fBTcl_SetMaxBlockTime\fR, \fBTcl_QueueEvent\fR, and \fBTcl_DeleteEvents\fR are used primarily by event sources. .IP [2] -The event queue: there is a single queue for the whole application, +The event queue: for non-threaded applications, +there is a single queue for the whole application, containing events that have been detected but not yet serviced. Event sources place events onto the queue so that they may be processed in order at appropriate times during the event loop. The event queue guarantees a fair discipline of event handling, so that no event source can starve the others. It also allows events to be saved for servicing at a future time. -.VS +.VS 8.1 +Threaded applications work in a +similar manner, except that there is a separate event queue for +each thread containing a Tcl interpreter. \fBTcl_QueueEvent\fR is used (primarily by event sources) to add events to the event queue and \fBTcl_DeleteEvents\fR is used to remove events from the queue without -processing them. See the manual entry for \fBThread\fR for a -description of the \fBTcl_ThreadQueueEvent\fR procedure. - +processing them. In a threaded application, \fBTcl_QueueEvent\fR adds +an event to the current thread's queue, and \fBTcl_ThreadQueueEvent\fR +adds an event to a queue in a specific thread. .IP [3] The event loop: in order to detect and process events, the application enters a loop that waits for events to occur, places them on the event @@ -146,7 +161,9 @@ to be retargeted either for a new platform or to use an external event loop (such as the Motif event loop, when Tcl is embedded in a Motif application). The procedures \fBTcl_WaitForEvent\fR and \fBTcl_SetTimer\fR are normally implemented by Tcl, but may be -replaced with new versions to retarget the notifier (the \fBTcl_Sleep\fR, +replaced with new versions to retarget the notifier (the +\fBTcl_InitNotifier\fR, \fBTcl_AlertNotifier\fR, +\fBTcl_FinalizeNotifier\fR, \fBTcl_Sleep\fR, \fBTcl_CreateFileHandler\fR, and \fBTcl_DeleteFileHandler\fR must also be replaced; see CREATING A NEW NOTIFIER below for details). The procedures \fBTcl_ServiceAll\fR, \fBTcl_ServiceEvent\fR, @@ -165,7 +182,7 @@ things: .IP [1] Check the event queue to see if it contains any events that can be serviced. If so, service the first possible event, remove it -.VS +.VS 8.1 from the queue, and return. It does this by calling \fBTcl_ServiceEvent\fR and passing in the \fIflags\fR argument. .VE @@ -173,7 +190,7 @@ from the queue, and return. It does this by calling Prepare to block for an event. To do this, \fBTcl_DoOneEvent\fR invokes a \fIsetup procedure\fR in each event source. The event source will perform event-source specific initialization and -.VS +.VS 8.1 possibly call \fBTcl_SetMaxBlockTime\fR to limit how long .VE \fBTcl_WaitForEvent\fR will block if no new events occur. @@ -241,7 +258,7 @@ request notification with a Windows event. For timer-driven event sources such as timer events or any polled event, the event source can call \fBTcl_SetMaxBlockTime\fR to force the application to wake up after a specified time even if no events have occurred. -.VS +.VS 8.1 If no event source calls \fBTcl_SetMaxBlockTime\fR then \fBTcl_WaitForEvent\fR will wait as long as necessary for an event to occur; otherwise, it will only wait as long as the shortest @@ -265,7 +282,7 @@ typedef struct Tcl_Time { .CE The \fIusec\fR field should be less than 1000000. .PP -.VS +.VS 8.1 Information provided to \fBTcl_SetMaxBlockTime\fR is only used for the next call to \fBTcl_WaitForEvent\fR; it is discarded after \fBTcl_WaitForEvent\fR returns. @@ -274,7 +291,7 @@ The next time an event wait is done each of the event sources' setup procedures will be called again, and they can specify new information for that event wait. .PP -.VS +.VS 8.1 If the application uses an external event loop rather than \fBTcl_DoOneEvent\fR, the event sources may need to call \fBTcl_SetMaxBlockTime\fR at other times. For example, if a new event @@ -348,7 +365,7 @@ events at the front of the queue, such as a series of Enter and Leave events synthesized during a grab or ungrab operation in Tk. .PP -.VS +.VS 8.1 When it is time to handle an event from the queue (steps 1 and 4 above) \fBTcl_ServiceEvent\fR will invoke the \fIproc\fR specified .VE @@ -363,7 +380,7 @@ The first argument to \fIproc\fR is a pointer to the event, which will be the same as the first argument to the \fBTcl_QueueEvent\fR call that added the event to the queue. The second argument to \fIproc\fR is the \fIflags\fR argument for the -.VS +.VS 8.1 current call to \fBTcl_ServiceEvent\fR; this is used by the event source .VE to return immediately if its events are not relevant. @@ -374,7 +391,7 @@ Once the event source has finished handling the event it returns 1 to indicate that the event can be removed from the queue. If for some reason the event source decides that the event cannot be handled at this time, it may return 0 to indicate that the event -.VS +.VS 8.1 should be deferred for processing later; in this case \fBTcl_ServiceEvent\fR .VE will go on to the next event in the queue and attempt to service it. @@ -387,7 +404,7 @@ Another example of deferring events happens in Tk if \fBTk_RestrictEvents\fR has been invoked to defer certain kinds of window events. .PP -.VS +.VS 8.1 When \fIproc\fR returns 1, \fBTcl_ServiceEvent\fR will remove the event from the event queue and free its storage. Note that the storage for an event must be allocated by @@ -395,6 +412,21 @@ the event source (using \fBTcl_Alloc\fR or the Tcl macro \fBckalloc\fR) before calling \fBTcl_QueueEvent\fR, but it will be freed by \fBTcl_ServiceEvent\fR, not by the event source. .PP +Threaded applications work in a +similar manner, except that there is a separate event queue for +each thread containing a Tcl interpreter. +Calling \fBTcl_QueueEvent\fR in a multithreaded application adds +an event to the current thread's queue. +To add an event to another thread's queue, use \fBTcl_ThreadQueueEvent\fR. +\fBTcl_ThreadQueueEvent\fR accepts as an argument a Tcl_ThreadId argument, +which uniquely identifies a thread in a Tcl application. To obtain the +Tcl_ThreadID for the current thread, use the \fBTcl_GetCurrentThread\fR +procedure. (A thread would then need to pass this identifier to other +threads for those threads to be able to add events to its queue.) +After adding an event to another thread's queue, you then typically +need to call \fBTcl_ThreadAlert\fR to "wake up" that thread's notifier to +alert it to the new event. +.PP \fBTcl_DeleteEvents\fR can be used to explicitly remove one or more events from the event queue. \fBTcl_DeleteEvents\fR calls \fIproc\fR for each event in the queue, deleting those for with the procedure @@ -409,13 +441,18 @@ The \fIclientData\fR argument will be the same as the \fIclientData\fR argument to \fBTcl_DeleteEvents\fR; it is typically used to point to private information managed by the event source. The \fIevPtr\fR will point to the next event in the queue. +.PP +\fBTcl_DeleteEventSource\fR deletes an event source. The \fIsetupProc\fR, +\fIcheckProc\fR, and \fIclientData\fR arguments must exactly match those +provided to the \fBTcl_CreateEventSource\fR for the event source to be deleted. +If no such source exists, \fBTcl_DeleteEventSource\fR has no effect. .VE .SH "CREATING A NEW NOTIFIER" .PP The notifier consists of all the procedures described in this manual entry, plus \fBTcl_DoOneEvent\fR and \fBTcl_Sleep\fR, which are -.VS +.VS 8.1 available on all platforms, and \fBTcl_CreateFileHandler\fR and \fBTcl_DeleteFileHandler\fR, which are Unix-specific. Most of these procedures are generic, in that they are the same for all notifiers. @@ -427,6 +464,12 @@ support a new platform or to integrate Tcl with an application-specific event loop, you must write new versions of these procedures. .PP +\fBTcl_InitNotifier\fR initializes the notifier state and returns +a handle to the notifier state. Tcl calls this +procedure when intializing a Tcl interpreter. Similarly, +\fBTcl_FinalizeNotifier\fR shuts down the notifier, and is +called by \Tcl_Finalize\fR when shutting down a Tcl interpreter. +.PP \fBTcl_WaitForEvent\fR is the lowest-level procedure in the notifier; it is responsible for waiting for an ``interesting'' event to occur or for a given time to elapse. Before \fBTcl_WaitForEvent\fR is invoked, @@ -462,6 +505,11 @@ under Unix it happens when \fBTcl_WaitForEvent\fR would have waited forever because there were no active event sources and the timeout was infinite. .PP +\fBTcl_AlertNotifier\fR is used in multithreaded applications to allow +any thread to "wake up" the notifier to alert it to new events on its +queue. \fBTcl_AlertNotifier\fR requires as an argument the notifier +handle returned by \fBTcl_InitNotifier\fR. +.PP If the notifier will be used with an external event loop, then it must also support the \fBTcl_SetTimer\fR interface. \fBTcl_SetTimer\fR is invoked by \fBTcl_SetMaxBlockTime\fR whenever the maximum blocking @@ -476,10 +524,11 @@ notifier will only be used from \fBTcl_DoOneEvent\fR, then On Unix systems, the file event source also needs support from the notifier. The file event source consists of the \fBTcl_CreateFileHandler\fR and \fBTcl_DeleteFileHandler\fR -procedures, which are described elsewhere. +procedures, which are described in the \fBTcl_CreateFileHandler\fR +manual page. .PP The \fBTcl_Sleep\fR and \fBTcl_DoOneEvent\fR interfaces are described -elsewhere. +in their respective manual pages. .PP The easiest way to create a new notifier is to look at the code for an existing notifier, such as the files \fBunix/tclUnixNotfy.c\fR @@ -546,6 +595,8 @@ mode, which should be restored when the recursive loop exits. \fBTcl_GetServiceMode\fR returns the current value of the service mode. .VE - +.SH "SEE ALSO" +\fBTcl_CreateFileHandler\fR, \fBTcl_DeleteFileHandler\fR, \fBTcl_Sleep\fR, +\fBTcl_DoOneEvent\fR, \fBThreads.3\fR .SH KEYWORDS -event, notifier, event queue, event sources, file events, timer, idle, service mode +event, notifier, event queue, event sources, file events, timer, idle, service mode, threads |