Tcl Source Code

'\"
'\" Copyright (c) 1989-1993 The Regents of the University of California.
'\" Copyright (c) 1994-1996 Sun Microsystems, Inc.
'\"
'\" See the file "license.terms" for information on usage and redistribution
'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
'\"
.TH Tcl_AsyncCreate 3 7.0 Tcl "Tcl Library Procedures"
.so man.macros
.BS
.SH NAME
Tcl_AsyncCreate, Tcl_AsyncMark, Tcl_AsyncMarkFromSignal, Tcl_AsyncInvoke, Tcl_AsyncDelete, Tcl_AsyncReady \- handle asynchronous events
.SH SYNOPSIS
.nf
\fB#include <tcl.h>\fR
.sp
Tcl_AsyncHandler
\fBTcl_AsyncCreate\fR(\fIproc, clientData\fR)
.sp
void
\fBTcl_AsyncMark\fR(\fIasync\fR)
.sp
int
\fBTcl_AsyncMarkFromSignal\fR(\fIasync\fR, \fIsigNumber\fR)
.sp
int
\fBTcl_AsyncInvoke\fR(\fIinterp, code\fR)
.sp
void
\fBTcl_AsyncDelete\fR(\fIasync\fR)
.sp
int
\fBTcl_AsyncReady\fR()
.SH ARGUMENTS
.AS Tcl_AsyncHandler clientData
.AP Tcl_AsyncProc *proc in
Procedure to invoke to handle an asynchronous event.
.AP ClientData clientData in
One-word value to pass to \fIproc\fR.
.AP Tcl_AsyncHandler async in
Token for asynchronous event handler.
.AP int sigNumber in
POSIX signal number, when used in a signal context.
.AP Tcl_Interp *interp in
Tcl interpreter in which command was being evaluated when handler was
invoked, or NULL if handler was invoked when there was no interpreter
active.
.AP int code in
Completion code from command that just completed in \fIinterp\fR,
or 0 if \fIinterp\fR is NULL.

allocation could have been in progress when the event occurred.
The only safe approach is to set a flag indicating that the event
occurred, then handle the event later when the world has returned
to a clean state, such as after the current Tcl command completes.
.PP
\fBTcl_AsyncCreate\fR, \fBTcl_AsyncDelete\fR, and \fBTcl_AsyncReady\fR
are thread sensitive.  They access and/or set a thread-specific data
structure in the event of a core built with \fI\-\-enable\-threads\fR.
The token created by \fBTcl_AsyncCreate\fR contains the needed thread
information it was called from so that calling \fBTcl_AsyncMarkFromSignal\fR
or \fBTcl_AsyncMark\fR with this token will only yield the origin
thread into the asynchronous handler.
.PP
\fBTcl_AsyncCreate\fR creates an asynchronous handler and returns
a token for it.
The asynchronous handler must be created before
any occurrences of the asynchronous event that it is intended
to handle (it is not safe to create a handler at the time of
an event).
When an asynchronous event occurs the code that detects the event
(such as a POSIX signal handler) should call \fBTcl_AsyncMarkFromSignal\fR
with the token for the handler and the POSIX signal number. The
return value of this function is true, when the handler will be
marked, false otherwise.
For non-signal contexts, \fBTcl_AsyncMark\fR serves the same purpose.
\fBTcl_AsyncMarkFromSignal\fR and \fBTcl_AsyncMark\fR will mark
the handler as ready to execute, but will not invoke the handler
immediately. Tcl will call the \fIproc\fR associated with the
handler later, when the world is in a safe state, and \fIproc\fR
can then carry out the actions associated with the asynchronous event.
\fIProc\fR should have arguments and result that match the
type \fBTcl_AsyncProc\fR:
.PP
.CS
typedef int \fBTcl_AsyncProc\fR(
        ClientData \fIclientData\fR,
        Tcl_Interp *\fIinterp\fR,

}
declare 656 {
    const char *Tcl_UtfPrev(const char *src, const char *start)
}
declare 657 {
    int Tcl_UniCharIsUnicode(int ch)
}

# TIP #511
declare 660 {
    int Tcl_AsyncMarkFromSignal(Tcl_AsyncHandler async, int sigNumber)
}

# ----- BASELINE -- FOR -- 8.7.0 ----- #

##############################################################################

# Define the platform specific public Tcl interface. These functions are only
# available on the designated platform.

 * One of the following structures exists for each asynchronous handler:
 */

typedef struct AsyncHandler {
    int ready;			/* Non-zero means this handler should be
				 * invoked in the next call to
				 * Tcl_AsyncInvoke. */
    struct AsyncHandler *nextPtr, *prevPtr;
				/* Next, previous in list of all handlers
				 * for the process. */
    Tcl_AsyncProc *proc;	/* Procedure to call when handler is
				 * invoked. */
    ClientData clientData;	/* Value to pass to handler when it is
				 * invoked. */
    struct ThreadSpecificData *originTsd;
				/* Used in Tcl_AsyncMark to modify thread-
				 * specific data from outside the thread it is
				 * associated to. */
    Tcl_ThreadId originThrdId;	/* Origin thread where this token was created
				 * and where it will be yielded. */
    ClientData notifierData;	/* Platform notifier data or NULL. */
} AsyncHandler;

typedef struct ThreadSpecificData {







    int asyncReady;		/* This is set to 1 whenever a handler becomes
				 * ready and it is cleared to zero whenever
				 * Tcl_AsyncInvoke is called. It can be
				 * checked elsewhere in the application by
				 * calling Tcl_AsyncReady to see if
				 * Tcl_AsyncInvoke should be invoked. */
    int asyncActive;		/* Indicates whether Tcl_AsyncInvoke is
				 * currently working. If so then we won't set
				 * asyncReady again until Tcl_AsyncInvoke
				 * returns. */


} ThreadSpecificData;
static Tcl_ThreadDataKey dataKey;

/* Mutex to protect linked-list of AsyncHandlers in the process. */
TCL_DECLARE_MUTEX(asyncMutex)

/* List of all existing handlers of the process. */
static AsyncHandler *firstHandler = NULL;
static AsyncHandler *lastHandler = NULL;

/*
 *----------------------------------------------------------------------
 *
 * TclFinalizeAsync --
 *
 *	Finalizes the thread local data structure for the async
 *	subsystem.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Cleans up left-over async handlers for the calling thread.
 *
 *----------------------------------------------------------------------
 */

void
TclFinalizeAsync(void)
{
    AsyncHandler *token, *toDelete = NULL;
    Tcl_ThreadId self = Tcl_GetCurrentThread();

    Tcl_MutexLock(&asyncMutex);
    for (token = firstHandler; token != NULL;) {
	AsyncHandler *nextToken = token->nextPtr;

	if (token->originThrdId == self) {
	    if (token->prevPtr == NULL) {
		firstHandler = token->nextPtr;
		if (firstHandler == NULL) {
		    lastHandler = NULL;
		    break;
		}
	    } else {
		token->prevPtr->nextPtr = token->nextPtr;
		if (token == lastHandler) {
		    lastHandler = token->prevPtr;
		}
	    }
	    if (token->nextPtr != NULL) {
		token->nextPtr->prevPtr = token->prevPtr;
	    }
	    token->nextPtr = toDelete;
	    token->prevPtr = NULL;
	    toDelete = token;
	}
	token = nextToken;
    }
    Tcl_MutexUnlock(&asyncMutex);
    while (toDelete != NULL) {
	token = toDelete;
	toDelete = toDelete->nextPtr;
	ckfree(token);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_AsyncCreate --

{
    AsyncHandler *asyncPtr;
    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);

    asyncPtr = (AsyncHandler*)ckalloc(sizeof(AsyncHandler));
    asyncPtr->ready = 0;
    asyncPtr->nextPtr = NULL;
    asyncPtr->prevPtr = NULL;
    asyncPtr->proc = proc;
    asyncPtr->clientData = clientData;
    asyncPtr->originTsd = tsdPtr;
    asyncPtr->originThrdId = Tcl_GetCurrentThread();
    asyncPtr->notifierData = TclpNotifierData();

    Tcl_MutexLock(&asyncMutex);
    if (firstHandler == NULL) {
	firstHandler = asyncPtr;
    } else {
	asyncPtr->prevPtr = lastHandler;
	lastHandler->nextPtr = asyncPtr;
    }
    lastHandler = asyncPtr;
    Tcl_MutexUnlock(&asyncMutex);
    return (Tcl_AsyncHandler) asyncPtr;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_AsyncMark --

void
Tcl_AsyncMark(
    Tcl_AsyncHandler async)		/* Token for handler. */
{
    AsyncHandler *token = (AsyncHandler *) async;

    Tcl_MutexLock(&asyncMutex);
    token->ready = 1;
    if (!token->originTsd->asyncActive) {
	token->originTsd->asyncReady = 1;
	Tcl_ThreadAlert(token->originThrdId);
    }
    Tcl_MutexUnlock(&asyncMutex);

}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_AsyncMarkFromSignal --
 *
 *	This procedure is similar to Tcl_AsyncMark but must be used
 *	in POSIX signal contexts. In addition to Tcl_AsyncMark the
 *	signal number is passed.
 *
 * Results:
 *	True, when the handler will be marked, false otherwise.
 *
 * Side effects:
 *	The handler gets marked for invocation later.
 *
 *----------------------------------------------------------------------
 */

int
Tcl_AsyncMarkFromSignal(
    Tcl_AsyncHandler async,		/* Token for handler. */
    int sigNumber)			/* Signal number. */
{
#if TCL_THREADS
    AsyncHandler *token = (AsyncHandler *) async;

    return TclAsyncNotifier(sigNumber, token->originThrdId,
	    token->notifierData, &token->ready, -1);
#else
    Tcl_AsyncMark(async);
    return 1;
#endif
}

/*
 *----------------------------------------------------------------------
 *
 * TclAsyncMarkFromNotifier --
 *
 *	This procedure is called from the notifier thread and
 *	invokes Tcl_AsyncMark for specifically marked handlers.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Handlers get marked for invocation later.
 *
 *----------------------------------------------------------------------
 */

void
TclAsyncMarkFromNotifier(void)
{
    AsyncHandler *token;

    Tcl_MutexLock(&asyncMutex);
    for (token = firstHandler; token != NULL;
	    token = token->nextPtr) {
	if (token->ready == -1) {
	    token->ready = 1;
	    if (!token->originTsd->asyncActive) {
		token->originTsd->asyncReady = 1;
		Tcl_ThreadAlert(token->originThrdId);
	    }
	}
    }
    Tcl_MutexUnlock(&asyncMutex);
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_AsyncInvoke --
 *

				 * interpreter. Otherwise it is NULL. */
    int code)			/* If interp is non-NULL, this gives
				 * completion code from command that just
				 * completed. */
{
    AsyncHandler *asyncPtr;
    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
    Tcl_ThreadId self = Tcl_GetCurrentThread();

    Tcl_MutexLock(&asyncMutex);

    if (tsdPtr->asyncReady == 0) {
	Tcl_MutexUnlock(&asyncMutex);
	return code;
    }
    tsdPtr->asyncReady = 0;
    tsdPtr->asyncActive = 1;
    if (interp == NULL) {
	code = 0;
    }

    /*
     * Make one or more passes over the list of handlers, invoking at most one
     * handler in each pass. After invoking a handler, go back to the start of
     * the list again so that (a) if a new higher-priority handler gets marked
     * while executing a lower priority handler, we execute the higher-
     * priority handler next, and (b) if a handler gets deleted during the
     * execution of a handler, then the list structure may change so it isn't
     * safe to continue down the list anyway.
     */

    while (1) {
	for (asyncPtr = firstHandler; asyncPtr != NULL;
		asyncPtr = asyncPtr->nextPtr) {
	    if (asyncPtr->originThrdId != self) {
		continue;
	    }
	    if (asyncPtr->ready) {
		break;
	    }
	}
	if (asyncPtr == NULL) {
	    break;
	}
	asyncPtr->ready = 0;
	Tcl_MutexUnlock(&asyncMutex);
	code = asyncPtr->proc(asyncPtr->clientData, interp, code);
	Tcl_MutexLock(&asyncMutex);
    }
    tsdPtr->asyncActive = 0;
    Tcl_MutexUnlock(&asyncMutex);
    return code;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_AsyncDelete --

 *----------------------------------------------------------------------
 */

void
Tcl_AsyncDelete(
    Tcl_AsyncHandler async)		/* Token for handler to delete. */
{

    AsyncHandler *asyncPtr = (AsyncHandler *) async;


    /*
     * Assure early handling of the constraint
     */

    if (asyncPtr->originThrdId != Tcl_GetCurrentThread()) {
	Tcl_Panic("Tcl_AsyncDelete: async handler deleted by the wrong thread");
    }








    Tcl_MutexLock(&asyncMutex);



    if (asyncPtr->prevPtr == NULL) {
	firstHandler = asyncPtr->nextPtr;

	if (firstHandler == NULL) {
	    lastHandler = NULL;
	}


    } else {
	asyncPtr->prevPtr->nextPtr = asyncPtr->nextPtr;

	if (asyncPtr == lastHandler) {
	    lastHandler = asyncPtr->prevPtr;
	}
    }
    if (asyncPtr->nextPtr != NULL) {
	asyncPtr->nextPtr->prevPtr = asyncPtr->prevPtr;
    }
    Tcl_MutexUnlock(&asyncMutex);
    ckfree(asyncPtr);
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_AsyncReady --

EXTERN int		Tcl_UtfCharComplete(const char *src, int length);
/* 655 */
EXTERN const char *	Tcl_UtfNext(const char *src);
/* 656 */
EXTERN const char *	Tcl_UtfPrev(const char *src, const char *start);
/* 657 */
EXTERN int		Tcl_UniCharIsUnicode(int ch);
/* Slot 658 is reserved */
/* Slot 659 is reserved */
/* 660 */
EXTERN int		Tcl_AsyncMarkFromSignal(Tcl_AsyncHandler async,
				int sigNumber);

typedef struct {
    const struct TclPlatStubs *tclPlatStubs;
    const struct TclIntStubs *tclIntStubs;
    const struct TclIntPlatStubs *tclIntPlatStubs;
} TclStubHooks;

    char * (*tclGetStringFromObj) (Tcl_Obj *objPtr, size_t *lengthPtr); /* 651 */
    Tcl_UniChar * (*tclGetUnicodeFromObj) (Tcl_Obj *objPtr, size_t *lengthPtr); /* 652 */
    unsigned char * (*tclGetByteArrayFromObj) (Tcl_Obj *objPtr, size_t *lengthPtr); /* 653 */
    int (*tcl_UtfCharComplete) (const char *src, int length); /* 654 */
    const char * (*tcl_UtfNext) (const char *src); /* 655 */
    const char * (*tcl_UtfPrev) (const char *src, const char *start); /* 656 */
    int (*tcl_UniCharIsUnicode) (int ch); /* 657 */
    void (*reserved658)(void);
    void (*reserved659)(void);
    int (*tcl_AsyncMarkFromSignal) (Tcl_AsyncHandler async, int sigNumber); /* 660 */
} TclStubs;

extern const TclStubs *tclStubsPtr;

#ifdef __cplusplus
}
#endif

	(tclStubsPtr->tcl_UtfCharComplete) /* 654 */
#define Tcl_UtfNext \
	(tclStubsPtr->tcl_UtfNext) /* 655 */
#define Tcl_UtfPrev \
	(tclStubsPtr->tcl_UtfPrev) /* 656 */
#define Tcl_UniCharIsUnicode \
	(tclStubsPtr->tcl_UniCharIsUnicode) /* 657 */
/* Slot 658 is reserved */
/* Slot 659 is reserved */
#define Tcl_AsyncMarkFromSignal \
	(tclStubsPtr->tcl_AsyncMarkFromSignal) /* 660 */

#endif /* defined(USE_TCL_STUBS) */

/* !END!: Do not edit above this line. */

#undef TclUnusedStubEntry
#if defined(USE_TCL_STUBS)

MODULE_SCOPE void	TclArgumentBCEnter(Tcl_Interp *interp,
			    Tcl_Obj *objv[], int objc,
			    void *codePtr, CmdFrame *cfPtr, int cmd, int pc);
MODULE_SCOPE void	TclArgumentBCRelease(Tcl_Interp *interp,
			    CmdFrame *cfPtr);
MODULE_SCOPE void	TclArgumentGet(Tcl_Interp *interp, Tcl_Obj *obj,
			    CmdFrame **cfPtrPtr, int *wordPtr);
MODULE_SCOPE int	TclAsyncNotifier(int sigNumber, Tcl_ThreadId threadId,
			    ClientData clientData, int *flagPtr, int value);
MODULE_SCOPE void	TclAsyncMarkFromNotifier(void);
MODULE_SCOPE double	TclBignumToDouble(const void *bignum);
MODULE_SCOPE int	TclByteArrayMatch(const unsigned char *string,
			    int strLen, const unsigned char *pattern,
			    int ptnLen, int flags);
MODULE_SCOPE double	TclCeil(const void *a);
MODULE_SCOPE void	TclChannelPreserve(Tcl_Channel chan);
MODULE_SCOPE void	TclChannelRelease(Tcl_Channel chan);

MODULE_SCOPE int	TclpObjLstat(Tcl_Obj *pathPtr, Tcl_StatBuf *buf);
MODULE_SCOPE Tcl_Obj *	TclpTempFileName(void);
MODULE_SCOPE Tcl_Obj *  TclpTempFileNameForLibrary(Tcl_Interp *interp,
			    Tcl_Obj* pathPtr);
MODULE_SCOPE Tcl_Obj *	TclNewFSPathObj(Tcl_Obj *dirPtr, const char *addStrRep,
			    int len);
MODULE_SCOPE void	TclpAlertNotifier(ClientData clientData);
MODULE_SCOPE ClientData	TclpNotifierData(void);
MODULE_SCOPE void	TclpServiceModeHook(int mode);
MODULE_SCOPE void	TclpSetTimer(const Tcl_Time *timePtr);
MODULE_SCOPE int	TclpWaitForEvent(const Tcl_Time *timePtr);
MODULE_SCOPE void	TclpCreateFileHandler(int fd, int mask,
			    Tcl_FileProc *proc, ClientData clientData);
MODULE_SCOPE int	TclpDeleteFile(const void *path);
MODULE_SCOPE void	TclpDeleteFileHandler(int fd);

    TclGetStringFromObj, /* 651 */
    TclGetUnicodeFromObj, /* 652 */
    TclGetByteArrayFromObj, /* 653 */
    Tcl_UtfCharComplete, /* 654 */
    Tcl_UtfNext, /* 655 */
    Tcl_UtfPrev, /* 656 */
    Tcl_UniCharIsUnicode, /* 657 */
    0, /* 658 */
    0, /* 659 */
    Tcl_AsyncMarkFromSignal, /* 660 */
};

/* !END!: Do not edit above this line. */

 * The following static indicates if the notifier thread is running.
 *
 * You must hold the notifierInitLock before accessing this variable.
 */

static int notifierThreadRunning;

/*
 * The following static flag indicates that async handlers are pending.
 */

#if TCL_THREADS
static int asyncPending = 0;
#endif

/*
 * Signal mask information for notifier thread.
 */
static sigset_t notifierSigMask;
static sigset_t allSigMask;

/*
 * This is the thread ID of the notifier thread that does select. Only valid
 * when notifierThreadRunning is non-zero.
 *
 * You must hold the notifierInitLock before accessing this variable.
 */

    if (!notifierCount) {
	Tcl_Panic("StartNotifierThread: notifier not initialized");
    }
    if (!notifierThreadRunning) {
	int result;
	pthread_attr_t attr;

	/*
	 * Arrange for the notifier thread to start with all
	 * signals blocked. In its mainloop it unblocks the
	 * signals at safe points.
	 */

	sigfillset(&allSigMask);
	pthread_sigmask(SIG_BLOCK, &allSigMask, &notifierSigMask);

	pthread_attr_init(&attr);
	pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEM);
	pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);
	pthread_attr_setstacksize(&attr, 60 * 1024);
	result = pthread_create(&notifierThread, &attr,
		(void * (*)(void *)) NotifierThreadProc, NULL);
	pthread_attr_destroy(&attr);
	if (result) {
	    Tcl_Panic("StartNotifierThread: unable to start notifier thread");
	}
	notifierThreadRunning = 1;

	/*
	 * Restore original signal mask.
	 */

	pthread_sigmask(SIG_SETMASK, &notifierSigMask, NULL);
    }
    UNLOCK_NOTIFIER_INIT;
}


/*
 *----------------------------------------------------------------------

		int result = pthread_join(notifierThread, NULL);

		if (result) {
		    Tcl_Panic("Tcl_FinalizeNotifier: unable to join notifier "
			    "thread");
		}
		notifierThreadRunning = 0;

		/*
		 * If async marks are outstanding, perform actions now.
		 */
		if (asyncPending) {
		    asyncPending = 0;
		    TclAsyncMarkFromNotifier();
		}
	    }

	    close(receivePipe);
	    triggerPipe = -1;
	}
	CLOSE_NOTIFIER_LOG;
    }

	    }
	    UNLOCK_NOTIFIER_TSD;
	    filePtr->proc(filePtr->clientData, mask);
	}
    }
    return 1;
}

/*
 *----------------------------------------------------------------------
 *
 * TclpNotifierData --
 *
 *	This function returns a ClientData pointer to be associated
 *	with a Tcl_AsyncHandler.
 *
 * Results:
 *	On MacOSX, returns always NULL.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

ClientData
TclpNotifierData(void)
{
    return NULL;
}

/*
 *----------------------------------------------------------------------
 *
 * TclpWaitForEvent --
 *
 *	This function is called by Tcl_DoOneEvent to wait for new events on

    }
    return result;
}

/*
 *----------------------------------------------------------------------
 *
 * TclAsyncNotifier --
 *
 *	This procedure sets the async mark of an async handler to a
 *	given value, if it is called from the notifier thread.
 *
 * Result:
 *	True, when the handler will be marked, false otherwise.
 *
 * Side effetcs:
 *	The trigger pipe is written when called from the notifier
 *	thread.
 *
 *----------------------------------------------------------------------
 */

int
TclAsyncNotifier(
    int sigNumber,		/* Signal number. */
    TCL_UNUSED(Tcl_ThreadId),	/* Target thread. */
    TCL_UNUSED(ClientData),	/* Notifier data. */
    int *flagPtr,		/* Flag to mark. */
    int value)			/* Value of mark. */
{
#if TCL_THREADS
    /*
     * WARNING:
     * This code most likely runs in a signal handler. Thus,
     * only few async-signal-safe system calls are allowed,
     * e.g. pthread_self(), sem_post(), write().
     */

    if (pthread_equal(pthread_self(), (pthread_t) notifierThread)) {
	if (notifierThreadRunning) {
	    *flagPtr = value;
	    if (!asyncPending) {
		asyncPending = 1;
		write(triggerPipe, "S", 1);
	    }
	    return 1;
	}
	return 0;
    }

    /*
     * Re-send the signal to the notifier thread.
     */

    pthread_kill((pthread_t) notifierThread, sigNumber);
#endif
    return 0;
}

/*
 *----------------------------------------------------------------------
 *
 * NotifierThreadProc --
 *
 *	This routine is the initial (and only) function executed by the
 *	special notifier thread. Its job is to wait for file descriptors to
 *	become readable or writable or to have an exception condition and then
 *	to notify other threads who are interested in this information by
 *	signalling a condition variable. Other threads can signal this

static TCL_NORETURN void
NotifierThreadProc(
    TCL_UNUSED(ClientData))
{
    ThreadSpecificData *tsdPtr;
    fd_set readableMask, writableMask, exceptionalMask;
    int i, ret, numFdBits = 0, polling;
    struct timeval poll = {0., 0.}, *timePtr;
    char buf[2];

    /*
     * Look for file events and report them to interested threads.
     */

	 */

	if (receivePipe >= numFdBits) {
	    numFdBits = receivePipe + 1;
	}
	FD_SET(receivePipe, &readableMask);

	/*
	 * Signals are unblocked only during select().
	 */

	pthread_sigmask(SIG_SETMASK, &notifierSigMask, NULL);
	ret = select(numFdBits, &readableMask, &writableMask, &exceptionalMask,
		    timePtr);
	pthread_sigmask(SIG_BLOCK, &allSigMask, NULL);

	if (ret == -1) {
	    /*
	     * In case a signal was caught during select(),
	     * perform work on async handlers now.
	     */
	    if (errno == EINTR && asyncPending) {
		asyncPending = 0;
		TclAsyncMarkFromNotifier();
	    }

	    /*
	     * Try again immediately on an error.
	     */

	    continue;
	}

		 * Someone closed the write end of the pipe or sent us a Quit
		 * message [Bug: 4139] and then closed the write end of the
		 * pipe so we need to shut down the notifier thread.
		 */

		break;
	    }

	    if (asyncPending) {
		asyncPending = 0;
		TclAsyncMarkFromNotifier();
	    }
	}
    }
    pthread_exit(0);
}

#ifdef HAVE_PTHREAD_ATFORK
/*

    /*
     * If a child process unlocks an os_unfair_lock that was created in its
     * parent the child will exit with an illegal instruction error.  So we
     * reinitialize the lock in the child rather than attempt to unlock it.
     */

#if defined(USE_OS_UNFAIR_LOCK)
    notifierInitLock = OS_UNFAIR_LOCK_INIT;
    notifierLock     = OS_UNFAIR_LOCK_INIT;
    tsdPtr->tsdLock  = OS_UNFAIR_LOCK_INIT;
#else
    UNLOCK_NOTIFIER_TSD;
    UNLOCK_NOTIFIER;
    UNLOCK_NOTIFIER_INIT;
#endif

    asyncPending = 0;

    if (tsdPtr->runLoop) {
	tsdPtr->runLoop = NULL;
	if (!noCFafterFork) {
	    CFRunLoopSourceInvalidate(tsdPtr->runLoopSource);
	    CFRelease(tsdPtr->runLoopSource);
	    if (tsdPtr->runLoopTimer) {
		CFRunLoopTimerInvalidate(tsdPtr->runLoopTimer);

	 * executed in the main thread of the parent, otherwise
	 * Tcl_AlertNotifier may break in the child.
	 */

	if (!noCFafterFork) {
	    Tcl_InitNotifier();
	}

	/*
	 * Restart the notifier thread for signal handling.
	 */

	StartNotifierThread();
    }
}
#endif /* HAVE_PTHREAD_ATFORK */

#else /* HAVE_COREFOUNDATION */

void

	tcl_ok=yes
    fi
fi
if test $tcl_ok = no; then

printf "%s\n" "#define NO_FD_SET 1" >>confdefs.h

fi

{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for pselect" >&5
printf %s "checking for pselect... " >&6; }
if test ${tcl_cv_func_pselect+y}
then :
  printf %s "(cached) " >&6
else $as_nop

    cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h.  */
#include <sys/types.h>
int
main (void)
{
void *func = pselect;
  ;
  return 0;
}
_ACEOF
if ac_fn_c_try_compile "$LINENO"
then :
  tcl_cv_func_pselect=yes
else $as_nop
  tcl_cv_func_pselect=no
fi
rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
fi
{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $tcl_cv_func_pselect" >&5
printf "%s\n" "$tcl_cv_func_pselect" >&6; }
tcl_ok=$tcl_cv_func_pselect
if test $tcl_ok = yes; then

printf "%s\n" "#define HAVE_PSELECT 1" >>confdefs.h

fi

#------------------------------------------------------------------------
#	Options for the notifier. Checks for epoll(7) on Linux, and
#	kqueue(2) on {DragonFly,Free,Net,Open}BSD
#------------------------------------------------------------------------

	AC_DEFINE(HAVE_SYS_SELECT_H, 1, [Should we include <sys/select.h>?])
	tcl_ok=yes
    fi
fi
if test $tcl_ok = no; then
    AC_DEFINE(NO_FD_SET, 1, [Do we have fd_set?])
fi

AC_CACHE_CHECK([for pselect], tcl_cv_func_pselect, [
    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <sys/types.h>]], [[void *func = pselect;]])],[tcl_cv_func_pselect=yes],[tcl_cv_func_pselect=no])])
tcl_ok=$tcl_cv_func_pselect
if test $tcl_ok = yes; then
    AC_DEFINE(HAVE_PSELECT, 1, [Should we use pselect()?])
fi

#------------------------------------------------------------------------
#	Options for the notifier. Checks for epoll(7) on Linux, and
#	kqueue(2) on {DragonFly,Free,Net,Open}BSD
#------------------------------------------------------------------------

AC_MSG_CHECKING([for advanced notifier support])

#undef HAVE_OSSPINLOCKLOCK

/* Define to 1 if you have the `pthread_atfork' function. */
#undef HAVE_PTHREAD_ATFORK

/* Define to 1 if you have the `pthread_attr_setstacksize' function. */
#undef HAVE_PTHREAD_ATTR_SETSTACKSIZE

/* Define to 1 if you have the `pselect' function */
#undef HAVE_PSELECT

/* Does putenv() copy strings or incorporate them by reference? */
#undef HAVE_PUTENV_THAT_COPIES

/* Are characters signed? */
#undef HAVE_SIGNED_CHAR

#endif /* HAVE_EVENTFD */
    int eventsFd;		/* epoll(7) file descriptor used to wait for
				 * fds */
    struct epoll_event *readyEvents;
				/* Pointer to at most maxReadyEvents events
				 * returned by epoll_wait(2). */
    size_t maxReadyEvents;	/* Count of epoll_events in readyEvents. */
    int asyncPending;		/* True when signal triggered thread. */
} ThreadSpecificData;

static Tcl_ThreadDataKey dataKey;

/*
 * Forward declarations.
 */

	if (!timercmp(&tv_delta, timePtr, >)) {
	    timersub(timePtr, &tv_delta, timePtr);
	} else {
	    timePtr->tv_sec = 0;
	    timePtr->tv_usec = 0;
	}
    }
    if (tsdPtr->asyncPending) {
	tsdPtr->asyncPending = 0;
	TclAsyncMarkFromNotifier();
    }
    return numFound;
}

/*
 *----------------------------------------------------------------------
 *
 * TclpCreateFileHandler --

	    fileEvPtr->fd = filePtr->fd;
	    Tcl_QueueEvent((Tcl_Event *) fileEvPtr, TCL_QUEUE_TAIL);
	}
	filePtr->readyMask = mask;
    }
    return 0;
}

/*
 *----------------------------------------------------------------------
 *
 * TclAsyncNotifier --
 *
 *	This procedure sets the async mark of an async handler to a
 *	given value, if it is called from the target thread.
 *
 * Result:
 *	True, when the handler will be marked, false otherwise.
 *
 * Side effects:
 *	The signal may be resent to the target thread.
 *
 *----------------------------------------------------------------------
 */

int
TclAsyncNotifier(
    int sigNumber,		/* Signal number. */
    Tcl_ThreadId threadId,	/* Target thread. */
    ClientData clientData,	/* Notifier data. */
    int *flagPtr,		/* Flag to mark. */
    int value)			/* Value of mark. */
{
#if TCL_THREADS
    /*
     * WARNING:
     * This code most likely runs in a signal handler. Thus,
     * only few async-signal-safe system calls are allowed,
     * e.g. pthread_self(), sem_post(), write().
     */

    if (pthread_equal(pthread_self(), (pthread_t) threadId)) {
	ThreadSpecificData *tsdPtr = (ThreadSpecificData *) clientData;

	*flagPtr = value;
	if (tsdPtr != NULL && !tsdPtr->asyncPending) {
	    tsdPtr->asyncPending = 1;
	    TclpAlertNotifier(tsdPtr);
	    return 1;
	}
	return 0;
    }

    /*
     * Re-send the signal to the proper target thread.
     */

    pthread_kill((pthread_t) threadId, sigNumber);
#endif
    return 0;
}

#endif /* NOTIFIER_EPOLL && TCL_THREADS */
#else
TCL_MAC_EMPTY_FILE(unix_tclEpollNotfy_c)
#endif /* !HAVE_COREFOUNDATION */

/*
 * Local Variables:
 * mode: c
 * c-basic-offset: 4
 * fill-column: 78
 * End:
 */

    int triggerPipe[2];		/* pipe(2) used by other threads to wake
				 * up this thread for inter-thread IPC. */
    int eventsFd;		/* kqueue(2) file descriptor used to wait for
				 * fds. */
    struct kevent *readyEvents;	/* Pointer to at most maxReadyEvents events
				 * returned by kevent(2). */
    size_t maxReadyEvents;	/* Count of kevents in readyEvents. */
    int asyncPending;		/* True when signal triggered thread. */
} ThreadSpecificData;

static Tcl_ThreadDataKey dataKey;

/*
 * Forward declarations of internal functions.
 */

{
    int numChanges;
    struct kevent changeList[2];
    struct PlatformEventData *newPedPtr;
    Tcl_StatBuf fdStat;

    if (isNew) {
	newPedPtr = (struct PlatformEventData *)
		ckalloc(sizeof(struct PlatformEventData));
	newPedPtr->filePtr = filePtr;
	newPedPtr->tsdPtr = tsdPtr;
	filePtr->pedPtr = newPedPtr;
    }

    /*
     * N.B. As discussed in Tcl_WaitForEvent(), kqueue(2) does not reproduce
     * the `always ready' {select,poll}(2) behaviour for regular files
     * (S_IFREG) prior to FreeBSD 11.0-RELEASE. Therefore, filePtr is in these
     * cases simply added or deleted from the list of FileHandlers associated

	    numChanges++;
	}
	if (filePtr->mask & TCL_WRITABLE) {
	    EV_SET(&changeList[numChanges], (uintptr_t) filePtr->fd,
		    EVFILT_WRITE, op, 0, 0, filePtr->pedPtr);
	    numChanges++;
	}
	if (numChanges) {
	    if (kevent(tsdPtr->eventsFd, changeList, numChanges, NULL, 0,
		    NULL) == -1) {
		Tcl_Panic("kevent: %s", strerror(errno));
	    }
	}
	break;
    case EV_DELETE:

	Tcl_Panic("fcntl: %s", strerror(errno));
    }
    filePtr = (FileHandler *) ckalloc(sizeof(FileHandler));
    filePtr->fd = tsdPtr->triggerPipe[0];
    filePtr->mask = TCL_READABLE;
    PlatformEventsControl(filePtr, tsdPtr, EV_ADD, 1);
    if (!tsdPtr->readyEvents) {
	tsdPtr->maxReadyEvents = 512;
	tsdPtr->readyEvents = (struct kevent *) ckalloc(
		tsdPtr->maxReadyEvents * sizeof(tsdPtr->readyEvents[0]));
    }
    LIST_INIT(&tsdPtr->firstReadyFileHandlerPtr);

    return tsdPtr;
}

	timersub(&tv1, &tv0, &tv_delta);
	if (!timercmp(&tv_delta, timePtr, >)) {
	    timersub(timePtr, &tv_delta, timePtr);
	} else {
	    timePtr->tv_sec = 0;
	    timePtr->tv_usec = 0;
	}
    }
    if (tsdPtr->asyncPending) {
	tsdPtr->asyncPending = 0;
	TclAsyncMarkFromNotifier();
    }
    return numFound;
}

/*
 *----------------------------------------------------------------------
 *

	    fileEvPtr->fd = filePtr->fd;
	    Tcl_QueueEvent((Tcl_Event *) fileEvPtr, TCL_QUEUE_TAIL);
	}
	filePtr->readyMask |= mask;
    }
    return 0;
}

/*
 *----------------------------------------------------------------------
 *
 * TclAsyncNotifier --
 *
 *	This procedure sets the async mark of an async handler to a
 *	given value, if it is called from the target thread.
 *
 * Result:
 *	True, when the handler will be marked, false otherwise.
 *
 * Side effects:
 *	The signal may be resent to the target thread.
 *
 *----------------------------------------------------------------------
 */

int
TclAsyncNotifier(
    int sigNumber,		/* Signal number. */
    Tcl_ThreadId threadId,	/* Target thread. */
    ClientData clientData,	/* Notifier data. */
    int *flagPtr,		/* Flag to mark. */
    int value)			/* Value of mark. */
{
#if TCL_THREADS
    /*
     * WARNING:
     * This code most likely runs in a signal handler. Thus,
     * only few async-signal-safe system calls are allowed,
     * e.g. pthread_self(), sem_post(), write().
     */

    if (pthread_equal(pthread_self(), (pthread_t) threadId)) {
	ThreadSpecificData *tsdPtr = (ThreadSpecificData *) clientData;

	*flagPtr = value;
	if (tsdPtr != NULL && !tsdPtr->asyncPending) {
	    tsdPtr->asyncPending = 1;
	    TclpAlertNotifier(tsdPtr);
	    return 1;
	}
	return 0;
    }

    /*
     * Re-send the signal to the proper target thread.
     */

    pthread_kill((pthread_t) threadId, sigNumber);
#endif
    return 0;
}

#endif /* NOTIFIER_KQUEUE && TCL_THREADS */
#else
TCL_MAC_EMPTY_FILE(unix_tclKqueueNotfy_c)
#endif /* !HAVE_COREFOUNDATION */

/*
 * Local Variables:
 * mode: c
 * c-basic-offset: 4
 * fill-column: 78
 * End:
 */

 * pipe. Hence writing to this file descriptor will cause the select() system
 * call to return and wake up the notifier thread.
 *
 * You must hold the notifierMutex lock before writing to the pipe.
 */

static int triggerPipe = -1;
static int otherPipe = -1;

/*
 * The notifierMutex locks access to all of the global notifier state.
 */

static pthread_mutex_t notifierInitMutex = PTHREAD_MUTEX_INITIALIZER;
static pthread_mutex_t notifierMutex     = PTHREAD_MUTEX_INITIALIZER;
/*
 * The following static indicates if the notifier thread is running.
 *
 * You must hold the notifierInitMutex before accessing this variable.
 */

static int notifierThreadRunning = 0;

/*
 * The following static flag indicates that async handlers are pending.
 */

static int asyncPending = 0;

/*
 * The notifier thread signals the notifierCV when it has finished
 * initializing the triggerPipe and right before the notifier thread
 * terminates. This condition is used to deal with the signal mask, too.
 */

static pthread_cond_t notifierCV = PTHREAD_COND_INITIALIZER;

/*
 * The pollState bits:
 *

#define POLL_DONE	0x2

/*
 * This is the thread ID of the notifier thread that does select.
 */

static Tcl_ThreadId notifierThread;

/*
 * Signal mask information for notifier thread.
 */

static sigset_t notifierSigMask;
static sigset_t allSigMask;

#endif /* TCL_THREADS */

/*
 * Static routines defined in this file.
 */

#if TCL_THREADS

	    int result = pthread_join((pthread_t) notifierThread, NULL);

	    if (result) {
		Tcl_Panic("Tcl_FinalizeNotifier: %s",
			"unable to join notifier thread");
	    }
	    notifierThreadRunning = 0;

	    /*
	     * If async marks are outstanding, perform actions now.
	     */
	    if (asyncPending) {
		asyncPending = 0;
		TclAsyncMarkFromNotifier();
	    }
	}
    }

    /*
     * Clean up any synchronization objects in the thread local storage.
     */

#endif /* TCL_THREADS */
    return 0;
}

/*
 *----------------------------------------------------------------------
 *
 * TclAsyncNotifier --
 *
 *	This procedure sets the async mark of an async handler to a
 *	given value, if it is called from the notifier thread.
 *
 * Result:
 *	True, when the handler will be marked, false otherwise.
 *
 * Side effetcs:
 *	The trigger pipe is written when called from the notifier
 *	thread.
 *
 *----------------------------------------------------------------------
 */

int
TclAsyncNotifier(
    int sigNumber,		/* Signal number. */
    Tcl_ThreadId threadId,	/* Target thread. */
    TCL_UNUSED(ClientData),	/* Notifier data. */
    int *flagPtr,		/* Flag to mark. */
    int value)			/* Value of mark. */
{
#if TCL_THREADS
    /*
     * WARNING:
     * This code most likely runs in a signal handler. Thus,
     * only few async-signal-safe system calls are allowed,
     * e.g. pthread_self(), sem_post(), write().
     */

    if (pthread_equal(pthread_self(), (pthread_t) notifierThread)) {
	if (notifierThreadRunning) {
	    *flagPtr = value;
	    if (!asyncPending) {
		asyncPending = 1;
		write(triggerPipe, "S", 1);
	    }
	    return 1;
	}
	return 0;
    }

    /*
     * Re-send the signal to the notifier thread.
     */

    pthread_kill((pthread_t) notifierThread, sigNumber);
#endif
    return 0;
}

/*
 *----------------------------------------------------------------------
 *
 * NotifierThreadProc --
 *
 *	This routine is the initial (and only) function executed by the
 *	special notifier thread. Its job is to wait for file descriptors to
 *	become readable or writable or to have an exception condition and then
 *	to notify other threads who are interested in this information by
 *	signalling a condition variable. Other threads can signal this

NotifierThreadProc(
    TCL_UNUSED(ClientData))
{
    ThreadSpecificData *tsdPtr;
    fd_set readableMask;
    fd_set writableMask;
    fd_set exceptionMask;

    int i, fds[2], receivePipe, ret;
    long found;
    struct timeval poll = {0, 0}, *timePtr;
    char buf[2];
    int numFdBits = 0;

    if (pipe(fds) != 0) {
	Tcl_Panic("NotifierThreadProc: %s", "could not create trigger pipe");
    }

    /*
     * Ticket [c6897e6e6a].
     */

    if (fds[0] >= FD_SETSIZE || fds[1] >= FD_SETSIZE) {
	Tcl_Panic("NotifierThreadProc: %s", "too many open files");
    }

    receivePipe = fds[0];

    if (TclUnixSetBlockingMode(receivePipe, TCL_MODE_NONBLOCKING) < 0) {
	Tcl_Panic("NotifierThreadProc: %s",
		"could not make receive pipe non blocking");
    }

    /*
     * Install the write end of the pipe into the global variable.
     */

    pthread_mutex_lock(&notifierMutex);
    triggerPipe = fds[1];
    otherPipe = fds[0];

    /*
     * Signal any threads that are waiting.
     */

    pthread_cond_broadcast(&notifierCV);
    pthread_mutex_unlock(&notifierMutex);

	 */

	if (receivePipe >= numFdBits) {
	    numFdBits = receivePipe + 1;
	}
	FD_SET(receivePipe, &readableMask);

	/*
	 * Signals are unblocked only during select().
	 */

#ifdef HAVE_PSELECT
	{
	    struct timespec tspec, *tspecPtr;

	    if (timePtr == NULL) {
		tspecPtr = NULL;
	    } else {
		tspecPtr = &tspec;
		tspecPtr->tv_sec = timePtr->tv_sec;
		tspecPtr->tv_nsec = timePtr->tv_usec * 1000;
	    }
	    ret = pselect(numFdBits, &readableMask, &writableMask,
			    &exceptionMask, tspecPtr, &notifierSigMask);
	}
#else
	pthread_sigmask(SIG_SETMASK, &notifierSigMask, NULL);
	ret = select(numFdBits, &readableMask, &writableMask, &exceptionMask,
			timePtr);
	pthread_sigmask(SIG_BLOCK, &allSigMask, NULL);
#endif

	if (ret == -1) {
	    /*

	     * In case a signal was caught during select(),
	     * perform work on async handlers now.
	     */
	    if (errno == EINTR && asyncPending) {
		asyncPending = 0;
		TclAsyncMarkFromNotifier();
	    }

	    /*
	     * Try again immediately on select() error.
	     */
	    continue;
	}

	/*
	 * Alert any threads that are waiting on a ready file descriptor.
	 */

		 * message [Bug: 4139] and then closed the write end of the
		 * pipe so we need to shut down the notifier thread.
		 */

		break;
	    }
	} while (1);

	if (asyncPending) {
	    asyncPending = 0;
	    TclAsyncMarkFromNotifier();
	}

	if ((i == 0) || (buf[0] == 'q')) {
	    break;
	}
    }

    /*
     * Clean up the read end of the pipe and signal any threads waiting on
     * termination of the notifier thread.
     */

    close(receivePipe);
    pthread_mutex_lock(&notifierMutex);
    triggerPipe = -1;
    otherPipe = -1;
    pthread_cond_broadcast(&notifierCV);
    pthread_mutex_unlock(&notifierMutex);

    TclpThreadExit(0);
}
#endif /* TCL_THREADS */


static void
AlertSingleThread(
    ThreadSpecificData *tsdPtr)
{
    tsdPtr->eventReady = 1;
    if (tsdPtr->onList) {
	/*
	 * Remove the ThreadSpecificData structure of this thread from the
	 * waiting list. This prevents us from continuously spinning on
	 * epoll_wait until the other threads runs and services the file
	 * event.
	 */

	if (tsdPtr->prevPtr) {
    	    tsdPtr->prevPtr->nextPtr = tsdPtr->nextPtr;
	} else {
    	    waitingListPtr = tsdPtr->nextPtr;
	}
	if (tsdPtr->nextPtr) {
    	    tsdPtr->nextPtr->prevPtr = tsdPtr->prevPtr;
	}
	tsdPtr->nextPtr = tsdPtr->prevPtr = NULL;
	tsdPtr->onList = 0;
	tsdPtr->pollState = 0;
    }
#ifdef __CYGWIN__
    PostMessageW(tsdPtr->hwnd, 1024, 0, 0);
#else /* !__CYGWIN__ */
    pthread_cond_broadcast(&tsdPtr->waitCV);
#endif /* __CYGWIN__ */
}

    if (notifierThreadRunning == 1) {
	pthread_cond_destroy(&notifierCV);
    }
    pthread_mutex_init(&notifierInitMutex, NULL);
    pthread_mutex_init(&notifierMutex, NULL);
    pthread_cond_init(&notifierCV, NULL);

#ifdef NOTIFIER_SELECT
    asyncPending = 0;
#endif

    /*
     * notifierThreadRunning == 1: thread is running, (there might be data in
     *		notifier lists)
     * atForkInit == 0: InitNotifier was never called
     * notifierCount != 0: unbalanced InitNotifier() / FinalizeNotifier calls
     * waitingListPtr != 0: there are threads currently waiting for events.
     */

    if (atForkInit == 1) {

	notifierCount = 0;
	if (notifierThreadRunning == 1) {
	    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
	    notifierThreadRunning = 0;

	    close(triggerPipe);
	    triggerPipe = -1;
#ifdef NOTIFIER_SELECT
	    close(otherPipe);
	    otherPipe = -1;
#endif
	    /*
	     * The waitingListPtr might contain event info from multiple
	     * threads, which are invalid here, so setting it to NULL is not
	     * unreasonable.
	     */
	    waitingListPtr = NULL;

	     * The list of registered event handlers at fork time is in
	     * tsdPtr->firstFileHandlerPtr;
	     */
	}
    }

    Tcl_InitNotifier();

#ifdef NOTIFIER_SELECT
    /*
     * Restart the notifier thread for signal handling.
     */

    StartNotifierThread("AtForkChild");
#endif
}
#endif /* HAVE_PTHREAD_ATFORK */
#endif /* TCL_THREADS */
#endif /* NOTIFIER_SELECT */

/*
 *----------------------------------------------------------------------
 *
 * TclpNotifierData --
 *
 *	This function returns a ClientData pointer to be associated
 *	with a Tcl_AsyncHandler.
 *
 * Results:
 *	For the epoll and kqueue notifiers, this function returns the
 *	thread specific data. Otherwise NULL.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

ClientData
TclpNotifierData(void)
{
#if defined(NOTIFIER_EPOLL) || defined(NOTIFIER_KQUEUE)
    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);

    return (ClientData) tsdPtr;
#else
    return NULL;
#endif
}

/*
 *----------------------------------------------------------------------
 *
 * TclUnixWaitForFile --
 *
 *	This function waits synchronously for a file to become readable or

	Tcl_AlertNotifier(tsdPtr);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * TclAsyncNotifier --
 *
 *	This procedure is a no-op on Windows.
 *
 * Result:
 *	Always true.
 *
 * Side effetcs:
 *	None.
 *----------------------------------------------------------------------
 */

int
TclAsyncNotifier(
    int sigNumber,		/* Signal number. */
    Tcl_ThreadId threadId,	/* Target thread. */
    ClientData clientData,	/* Notifier data. */
    int *flagPtr,		/* Flag to mark. */
    int value)			/* Value of mark. */
{
    return 0;
}

/*
 *----------------------------------------------------------------------
 *
 * NotifierProc --
 *
 *	This procedure is invoked by Windows to process events on the notifier
 *	window. Messages will be sent to this window in response to external
 *	timer events or calls to TclpAlertTsdPtr->
 *
 * Results:

    /*
     * Process all of the runnable events.
     */

    Tcl_ServiceAll();
    return 0;
}

/*
 *----------------------------------------------------------------------
 *
 * TclpNotifierData --
 *
 *	This function returns a ClientData pointer to be associated
 *	with a Tcl_AsyncHandler.
 *
 * Results:
 *	On Windows, returns always NULL.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

ClientData
TclpNotifierData(void)
{
    return NULL;
}

/*
 *----------------------------------------------------------------------
 *
 * TclpWaitForEvent --
 *
 *	This function is called by Tcl_DoOneEvent to wait for new events on