'\" 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 1.9 2002/07/01 18:24:39 jenglish Exp $
-'\"
-'\" The definitions below are for supplemental macros used in Tcl/Tk
-'\" manual entries.
-'\"
-'\" .AP type name in/out ?indent?
-'\" Start paragraph describing an argument to a library procedure.
-'\" type is type of argument (int, etc.), in/out is either "in", "out",
-'\" or "in/out" to describe whether procedure reads or modifies arg,
-'\" and indent is equivalent to second arg of .IP (shouldn't ever be
-'\" needed; use .AS below instead)
-'\"
-'\" .AS ?type? ?name?
-'\" Give maximum sizes of arguments for setting tab stops. Type and
-'\" name are examples of largest possible arguments that will be passed
-'\" to .AP later. If args are omitted, default tab stops are used.
-'\"
-'\" .BS
-'\" Start box enclosure. From here until next .BE, everything will be
-'\" enclosed in one large box.
-'\"
-'\" .BE
-'\" End of box enclosure.
-'\"
-'\" .CS
-'\" Begin code excerpt.
-'\"
-'\" .CE
-'\" End code excerpt.
-'\"
-'\" .VS ?version? ?br?
-'\" Begin vertical sidebar, for use in marking newly-changed parts
-'\" of man pages. The first argument is ignored and used for recording
-'\" the version when the .VS was added, so that the sidebars can be
-'\" found and removed when they reach a certain age. If another argument
-'\" is present, then a line break is forced before starting the sidebar.
-'\"
-'\" .VE
-'\" End of vertical sidebar.
-'\"
-'\" .DS
-'\" Begin an indented unfilled display.
-'\"
-'\" .DE
-'\" End of indented unfilled display.
-'\"
-'\" .SO
-'\" Start of list of standard options for a Tk widget. The
-'\" options follow on successive lines, in four columns separated
-'\" by tabs.
-'\"
-'\" .SE
-'\" End of list of standard options for a Tk widget.
-'\"
-'\" .OP cmdName dbName dbClass
-'\" Start of description of a specific option. cmdName gives the
-'\" option's name as specified in the class command, dbName gives
-'\" the option's name in the option database, and dbClass gives
-'\" the option's class in the option database.
-'\"
-'\" .UL arg1 arg2
-'\" Print arg1 underlined, then print arg2 normally.
-'\"
-'\" RCS: @(#) $Id: man.macros,v 1.4 2000/08/25 06:18:32 ericm Exp $
-'\"
-'\" # Set up traps and other miscellaneous stuff for Tcl/Tk man pages.
+.TH Notifier 3 8.1 Tcl "Tcl Library Procedures"
+.\" The -*- nroff -*- definitions below are for supplemental macros used
+.\" in Tcl/Tk manual entries.
+.\"
+.\" .AP type name in/out ?indent?
+.\" Start paragraph describing an argument to a library procedure.
+.\" type is type of argument (int, etc.), in/out is either "in", "out",
+.\" or "in/out" to describe whether procedure reads or modifies arg,
+.\" and indent is equivalent to second arg of .IP (shouldn't ever be
+.\" needed; use .AS below instead)
+.\"
+.\" .AS ?type? ?name?
+.\" Give maximum sizes of arguments for setting tab stops. Type and
+.\" name are examples of largest possible arguments that will be passed
+.\" to .AP later. If args are omitted, default tab stops are used.
+.\"
+.\" .BS
+.\" Start box enclosure. From here until next .BE, everything will be
+.\" enclosed in one large box.
+.\"
+.\" .BE
+.\" End of box enclosure.
+.\"
+.\" .CS
+.\" Begin code excerpt.
+.\"
+.\" .CE
+.\" End code excerpt.
+.\"
+.\" .VS ?version? ?br?
+.\" Begin vertical sidebar, for use in marking newly-changed parts
+.\" of man pages. The first argument is ignored and used for recording
+.\" the version when the .VS was added, so that the sidebars can be
+.\" found and removed when they reach a certain age. If another argument
+.\" is present, then a line break is forced before starting the sidebar.
+.\"
+.\" .VE
+.\" End of vertical sidebar.
+.\"
+.\" .DS
+.\" Begin an indented unfilled display.
+.\"
+.\" .DE
+.\" End of indented unfilled display.
+.\"
+.\" .SO ?manpage?
+.\" Start of list of standard options for a Tk widget. The manpage
+.\" argument defines where to look up the standard options; if
+.\" omitted, defaults to "options". The options follow on successive
+.\" lines, in three columns separated by tabs.
+.\"
+.\" .SE
+.\" End of list of standard options for a Tk widget.
+.\"
+.\" .OP cmdName dbName dbClass
+.\" Start of description of a specific option. cmdName gives the
+.\" option's name as specified in the class command, dbName gives
+.\" the option's name in the option database, and dbClass gives
+.\" the option's class in the option database.
+.\"
+.\" .UL arg1 arg2
+.\" Print arg1 underlined, then print arg2 normally.
+.\"
+.\" .QW arg1 ?arg2?
+.\" Print arg1 in quotes, then arg2 normally (for trailing punctuation).
+.\"
+.\" .PQ arg1 ?arg2?
+.\" Print an open parenthesis, arg1 in quotes, then arg2 normally
+.\" (for trailing punctuation) and then a closing parenthesis.
+.\"
+.\" # Set up traps and other miscellaneous stuff for Tcl/Tk man pages.
.if t .wh -1.3i ^B
.nr ^l \n(.l
.ad b
-'\" # Start an argument description
+.\" # Start an argument description
.de AP
.ie !"\\$4"" .TP \\$4
.el \{\
.\}
.ta \\n()Au \\n()Bu
.ie !"\\$3"" \{\
-\&\\$1 \\fI\\$2\\fP (\\$3)
+\&\\$1 \\fI\\$2\\fP (\\$3)
.\".b
.\}
.el \{\
.\}
.\}
..
-'\" # define tabbing values for .AP
+.\" # define tabbing values for .AP
.de AS
.nr )A 10n
.if !"\\$1"" .nr )A \\w'\\$1'u+3n
.nr )C \\n()Bu+\\w'(in/out)'u+2n
..
.AS Tcl_Interp Tcl_CreateInterp in/out
-'\" # BS - start boxed text
-'\" # ^y = starting y location
-'\" # ^b = 1
+.\" # BS - start boxed text
+.\" # ^y = starting y location
+.\" # ^b = 1
.de BS
.br
.mk ^y
.if n \l'\\n(.lu\(ul'
.if n .fi
..
-'\" # BE - end boxed text (draw box now)
+.\" # BE - end boxed text (draw box now)
.de BE
.nf
.ti 0
.br
.nr ^b 0
..
-'\" # VS - start vertical sidebar
-'\" # ^Y = starting y location
-'\" # ^v = 1 (for troff; for nroff this doesn't matter)
+.\" # VS - start vertical sidebar
+.\" # ^Y = starting y location
+.\" # ^v = 1 (for troff; for nroff this doesn't matter)
.de VS
.if !"\\$2"" .br
.mk ^Y
.ie n 'mc \s12\(br\s0
.el .nr ^v 1u
..
-'\" # VE - end of vertical sidebar
+.\" # VE - end of vertical sidebar
.de VE
.ie n 'mc
.el \{\
.\}
.nr ^v 0
..
-'\" # Special macro to handle page bottom: finish off current
-'\" # box/sidebar if in box/sidebar mode, then invoked standard
-'\" # page bottom macro.
+.\" # Special macro to handle page bottom: finish off current
+.\" # box/sidebar if in box/sidebar mode, then invoked standard
+.\" # page bottom macro.
.de ^B
.ev 2
'ti 0
.mk ^Y
.\}
..
-'\" # DS - begin display
+.\" # DS - begin display
.de DS
.RS
.nf
.sp
..
-'\" # DE - end display
+.\" # DE - end display
.de DE
.fi
.RE
.sp
..
-'\" # SO - start of list of standard options
+.\" # SO - start of list of standard options
.de SO
+'ie '\\$1'' .ds So \\fBoptions\\fR
+'el .ds So \\fB\\$1\\fR
.SH "STANDARD OPTIONS"
.LP
.nf
.ta 5.5c 11c
.ft B
..
-'\" # SE - end of list of standard options
+.\" # SE - end of list of standard options
.de SE
.fi
.ft R
.LP
-See the \\fBoptions\\fR manual entry for details on the standard options.
+See the \\*(So manual entry for details on the standard options.
..
-'\" # OP - start of full description for a single option
+.\" # OP - start of full description for a single option
.de OP
.LP
.nf
.fi
.IP
..
-'\" # CS - begin code excerpt
+.\" # CS - begin code excerpt
.de CS
.RS
.nf
.ta .25i .5i .75i 1i
..
-'\" # CE - end code excerpt
+.\" # CE - end code excerpt
.de CE
.fi
.RE
..
+.\" # UL - underline word
.de UL
\\$1\l'|0\(ul'\\$2
..
-.TH Notifier 3 8.1 Tcl "Tcl Library Procedures"
+.\" # QW - apply quotation marks to word
+.de QW
+.ie '\\*(lq'"' ``\\$1''\\$2
+.\"" fix emacs highlighting
+.el \\*(lq\\$1\\*(rq\\$2
+..
+.\" # PQ - apply parens and quotation marks to word
+.de PQ
+.ie '\\*(lq'"' (``\\$1''\\$2)\\$3
+.\"" fix emacs highlighting
+.el (\\*(lq\\$1\\*(rq\\$2)\\$3
+..
+.\" # QR - quoted range
+.de QR
+.ie '\\*(lq'"' ``\\$1''\\-``\\$2''\\$3
+.\"" fix emacs highlighting
+.el \\*(lq\\$1\\*(rq\\-\\*(lq\\$2\\*(rq\\$3
+..
+.\" # MT - "empty" string
+.de MT
+.QW ""
+..
.BS
.SH NAME
-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
+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, Tcl_ServiceModeHook, Tcl_SetNotifier \- the event queue and notifier interfaces
.SH SYNOPSIS
.nf
\fB#include <tcl.h>\fR
.sp
void
\fBTcl_QueueEvent\fR(\fIevPtr, position\fR)
-.VS 8.1
.sp
void
\fBTcl_ThreadQueueEvent\fR(\fIthreadId, evPtr, position\fR)
.sp
void
-\fBTcl_ThreadAlert\fR(\fIthreadId, clientData\fR)
+\fBTcl_ThreadAlert\fR(\fIthreadId\fR)
.sp
Tcl_ThreadId
\fBTcl_GetCurrentThread\fR()
int
\fBTcl_GetServiceMode\fR()
.sp
-int
+int
\fBTcl_SetServiceMode\fR(\fImode\fR)
-.VE
-
+.sp
+void
+\fBTcl_ServiceModeHook\fR(\fImode\fR)
+.sp
+void
+\fBTcl_SetNotifier\fR(\fInotifierProcPtr\fR)
.SH ARGUMENTS
-.AS Tcl_EventDeleteProc milliseconds
+.AS Tcl_EventDeleteProc *notifierProcPtr
.AP Tcl_EventSetupProc *setupProc in
Procedure to invoke to prepare for event wait in \fBTcl_DoOneEvent\fR.
.AP Tcl_EventCheckProc *checkProc in
.AP ClientData clientData in
Arbitrary one-word value to pass to \fIsetupProc\fR, \fIcheckProc\fR, or
\fIdeleteProc\fR.
-.AP Tcl_Time *timePtr in
+.AP "const Tcl_Time" *timePtr in
Indicates the maximum amount of time to wait for an event. This
is specified as an interval (how long to wait), not an absolute
time (when to wakeup). If the pointer passed to \fBTcl_WaitForEvent\fR
.AP int flags in
What types of events to service. These flags are the same as those
passed to \fBTcl_DoOneEvent\fR.
-.VS 8.1
.AP int mode in
Indicates whether events should be serviced by \fBTcl_ServiceAll\fR.
Must be one of \fBTCL_SERVICE_NONE\fR or \fBTCL_SERVICE_ALL\fR.
-.VE
+.AP Tcl_NotifierProcs* notifierProcPtr in
+Structure of function pointers describing notifier procedures that are
+to replace the ones installed in the executable. See
+\fBREPLACING THE NOTIFIER\fR for details.
.BE
-
.SH INTRODUCTION
.PP
The interfaces described here are used to customize the Tcl event
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 8.1
-Threaded applications work in a
+servicing at a future time. 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
to help connect Tcl's event loop to an external event loop such as
Motif's.
.SH "NOTIFIER BASICS"
-.VE
.PP
The easiest way to understand how the notifier works is to consider
what happens when \fBTcl_DoOneEvent\fR is called.
.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 8.1
from the queue, and return. It does this by calling
\fBTcl_ServiceEvent\fR and passing in the \fIflags\fR argument.
-.VE
.IP [2]
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 8.1
possibly call \fBTcl_SetMaxBlockTime\fR to limit how long
-.VE
\fBTcl_WaitForEvent\fR will block if no new events occur.
.IP [3]
Call \fBTcl_WaitForEvent\fR. This procedure is implemented differently
.IP [7]
Either return 0 to indicate that no events were ready, or go back to
step [2] if blocking was requested by the caller.
-
.SH "CREATING A NEW EVENT SOURCE"
.PP
An event source consists of three procedures invoked by the notifier,
Its arguments specify the setup procedure and check procedure for
the event source.
\fISetupProc\fR should match the following prototype:
+.PP
.CS
-typedef void Tcl_EventSetupProc(
- ClientData \fIclientData\fR,
- int \fIflags\fR);
+typedef void \fBTcl_EventSetupProc\fR(
+ ClientData \fIclientData\fR,
+ int \fIflags\fR);
.CE
+.PP
The \fIclientData\fR argument will be the same as the \fIclientData\fR
argument to \fBTcl_CreateEventSource\fR; it is typically used to
point to private information managed by the event source.
argument passed to \fBTcl_DoOneEvent\fR except that it will never
be 0 (\fBTcl_DoOneEvent\fR replaces 0 with \fBTCL_ALL_EVENTS\fR).
\fIFlags\fR indicates what kinds of events should be considered;
-if the bit corresponding to this event source isn't set, the event
+if the bit corresponding to this event source is not set, the event
source should return immediately without doing anything. For
example, the file event source checks for the \fBTCL_FILE_EVENTS\fR
bit.
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 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
\fBTcl_SetMaxBlockTime\fR with a 0 block time so that
\fBTcl_WaitForEvent\fR does not block if there is no new data on the X
connection.
-.VE
The \fItimePtr\fR argument to \fBTcl_WaitForEvent\fR points to
a structure that describes a time interval in seconds and
microseconds:
+.PP
.CS
typedef struct Tcl_Time {
- long \fIsec\fR;
- long \fIusec\fR;
-} Tcl_Time;
+ long \fIsec\fR;
+ long \fIusec\fR;
+} \fBTcl_Time\fR;
.CE
+.PP
The \fIusec\fR field should be less than 1000000.
.PP
-.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.
-.VE
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 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
\fIsetupProc\fR, if there is additional information needed by
\fBTcl_WaitForEvent\fR on that platform. For example, on Unix systems
the \fBTcl_CreateFileHandler\fR interface can be used to wait for file events.
-.VE
.PP
The second procedure provided by each event source is its check
procedure, indicated by the \fIcheckProc\fR argument to
\fBTcl_CreateEventSource\fR. \fICheckProc\fR must match the
following prototype:
+.PP
.CS
-typedef void Tcl_EventCheckProc(
- ClientData \fIclientData\fR,
- int \fIflags\fR);
+typedef void \fBTcl_EventCheckProc\fR(
+ ClientData \fIclientData\fR,
+ int \fIflags\fR);
.CE
+.PP
The arguments to this procedure are the same as those for \fIsetupProc\fR.
\fBCheckProc\fR is invoked by \fBTcl_DoOneEvent\fR after it has waited
for events. Presumably at least one event source is now prepared to
must be a structure of type \fBTcl_Event\fR, and the address of this
structure is used when communicating between the event source and the
rest of the notifier. A \fBTcl_Event\fR has the following definition:
+.PP
.CS
typedef struct {
Tcl_EventProc *\fIproc\fR;
struct Tcl_Event *\fInextPtr\fR;
-} Tcl_Event;
+} \fBTcl_Event\fR;
.CE
+.PP
The event source must fill in the \fIproc\fR field of
the event before calling \fBTcl_QueueEvent\fR.
The \fInextPtr\fR is used to link together the events in the queue
Enter and Leave events synthesized during a grab or ungrab operation
in Tk.
.PP
-.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
in the first queued \fBTcl_Event\fR structure.
\fIProc\fR must match the following prototype:
+.PP
.CS
-typedef int Tcl_EventProc(
- Tcl_Event *\fIevPtr\fR,
- int \fIflags\fR);
+typedef int \fBTcl_EventProc\fR(
+ Tcl_Event *\fIevPtr\fR,
+ int \fIflags\fR);
.CE
+.PP
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 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.
.PP
It is up to \fIproc\fR to handle the event, typically by invoking
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 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.
There are several reasons why an event source might defer an event.
One possibility is that events of this type are excluded by the
\fIflags\fR argument.
For example, the file event source will always return 0 if the
-\fBTCL_FILE_EVENTS\fR bit isn't set in \fIflags\fR.
+\fBTCL_FILE_EVENTS\fR bit is not set in \fIflags\fR.
Another example of deferring events happens in Tk if
\fBTk_RestrictEvents\fR has been invoked to defer certain kinds
of window events.
.PP
-.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
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
+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.
+need to call \fBTcl_ThreadAlert\fR to
+.QW "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
returns 1. Events for which the procedure returns 0 are left in the
queue. \fIProc\fR should match the following prototype:
+.PP
.CS
-typedef int Tcl_EventDeleteProc(
- Tcl_Event *\fIevPtr\fR,
- ClientData \fIclientData\fR);
+typedef int \fBTcl_EventDeleteProc\fR(
+ Tcl_Event *\fIevPtr\fR,
+ ClientData \fIclientData\fR);
.CE
+.PP
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
\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 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.
-However, eight of the procedures are notifier-dependent:
-\fBTcl_InitNotifier\fR, \fBTcl_AlertNotifier\fR, \fBTcl_FinalizeNotifier\fR,
-\fBTcl_SetTimer\fR, \fBTcl_Sleep\fR, \fBTcl_WaitForEvent\fR,
-\fBTcl_CreateFileHandler\fR and \fBTcl_DeleteFileHandler\fR. To
-support a new platform or to integrate Tcl with an
-application-specific event loop, you must write new versions of these
-procedures.
+However, none of the procedures are notifier-dependent:
+\fBTcl_InitNotifier\fR, \fBTcl_AlertNotifier\fR,
+\fBTcl_FinalizeNotifier\fR, \fBTcl_SetTimer\fR, \fBTcl_Sleep\fR,
+\fBTcl_WaitForEvent\fR, \fBTcl_CreateFileHandler\fR,
+\fBTcl_DeleteFileHandler\fR and \fBTcl_ServiceModeHook\fR. To 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
called by \fBTcl_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
+it is responsible for waiting for an
+.QW interesting
+event to occur or
for a given time to elapse. Before \fBTcl_WaitForEvent\fR is invoked,
each of the event sources' setup procedure will have been invoked.
The \fItimePtr\fR argument to
Later on, the
event sources will process the raw events and create Tcl_Events on
the event queue in their \fIcheckProc\fR procedures.
-However, on some platforms (such as Windows) this isn't possible;
+However, on some platforms (such as Windows) this is not possible;
events may be processed in \fBTcl_WaitForEvent\fR, including queuing
Tcl_Events and more (for example, callbacks for native widgets may be
invoked). The return value from \fBTcl_WaitForEvent\fR must be either
0, 1, or \-1. On platforms such as Windows where events get processed in
\fBTcl_WaitForEvent\fR, a return value of 1 means that there may be more
-events still pending that haven't been processed. This is a sign to the
+events still pending that have not been processed. This is a sign to the
caller that it must call \fBTcl_WaitForEvent\fR again if it wants all
pending events to be processed. A 0 return value means that calling
\fBTcl_WaitForEvent\fR again will not have any effect: either this is a
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
+any thread to
+.QW "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
time has been reduced. \fBTcl_SetTimer\fR should arrange for the
external event loop to invoke \fBTcl_ServiceAll\fR after the specified
interval even if no events have occurred. This interface is needed
-because \fBTcl_WaitForEvent\fR isn't invoked when there is an external
+because \fBTcl_WaitForEvent\fR is not invoked when there is an external
event loop. If the
notifier will only be used from \fBTcl_DoOneEvent\fR, then
\fBTcl_SetTimer\fR need not do anything.
.PP
+\fBTcl_ServiceModeHook\fR is called by the platform-independent portion
+of the notifier when client code makes a call to
+\fBTcl_SetServiceMode\fR. This hook is provided to support operating
+systems that require special event handling when the application is in
+a modal loop (the Windows notifier, for instance, uses this hook to
+create a communication window).
+.PP
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
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
or \fBwin/tclWinNotify.c\fR in the Tcl source distribution.
-
+.SH "REPLACING THE NOTIFIER"
+.PP
+A notifier that has been written according to the conventions above
+can also be installed in a running process in place of the standard
+notifier. This mechanism is used so that a single executable can be
+used (with the standard notifier) as a stand-alone program and reused
+(with a replacement notifier in a loadable extension) as an extension
+to another program, such as a Web browser plugin.
+.PP
+To do this, the extension makes a call to \fBTcl_SetNotifier\fR
+passing a pointer to a \fBTcl_NotifierProcs\fR data structure. The
+structure has the following layout:
+.PP
+.CS
+typedef struct Tcl_NotifierProcs {
+ Tcl_SetTimerProc *\fIsetTimerProc\fR;
+ Tcl_WaitForEventProc *\fIwaitForEventProc\fR;
+ Tcl_CreateFileHandlerProc *\fIcreateFileHandlerProc\fR;
+ Tcl_DeleteFileHandlerProc *\fIdeleteFileHandlerProc\fR;
+ Tcl_InitNotifierProc *\fIinitNotifierProc\fR;
+ Tcl_FinalizeNotifierProc *\fIfinalizeNotifierProc\fR;
+ Tcl_AlertNotifierProc *\fIalertNotifierProc\fR;
+ Tcl_ServiceModeHookProc *\fIserviceModeHookProc\fR;
+} \fBTcl_NotifierProcs\fR;
+.CE
+.PP
+Following the call to \fBTcl_SetNotifier\fR, the pointers given in
+the \fBTcl_NotifierProcs\fR structure replace whatever notifier had
+been installed in the process.
+.PP
+It is extraordinarily unwise to replace a running notifier. Normally,
+\fBTcl_SetNotifier\fR should be called at process initialization time
+before the first call to \fBTcl_InitNotifier\fR.
.SH "EXTERNAL EVENT LOOPS"
.PP
The notifier interfaces are designed so that Tcl can be embedded into
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, \fBThread(3)\fR
+Tcl_CreateFileHandler(3), Tcl_DeleteFileHandler(3), Tcl_Sleep(3),
+Tcl_DoOneEvent(3), Thread(3)
.SH KEYWORDS
event, notifier, event queue, event sources, file events, timer, idle, service mode, threads
OSDN Git Service
