698 lines
20 KiB
C
698 lines
20 KiB
C
/*
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* tclEvent.c --
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*
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* This file implements some general event related interfaces including
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* background errors, exit handlers, and the "vwait" and "update"
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* command procedures.
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*
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* Copyright (c) 1990-1994 The Regents of the University of California.
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* Copyright (c) 1994-1997 Sun Microsystems, Inc.
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*
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* See the file "license.terms" for information on usage and redistribution
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* of this file, and for a DISCLAIMER OF ALL WARRANTIES.
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*
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* SCCS: @(#) tclEvent.c 1.153 97/08/11 20:22:31
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*/
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#include "tclInt.h"
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#include "tclPort.h"
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/*
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* The data structure below is used to report background errors. One
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* such structure is allocated for each error; it holds information
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* about the interpreter and the error until bgerror can be invoked
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* later as an idle handler.
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*/
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typedef struct BgError {
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Tcl_Interp *interp; /* Interpreter in which error occurred. NULL
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* means this error report has been cancelled
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* (a previous report generated a break). */
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char *errorMsg; /* The error message (interp->result when
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* the error occurred). Malloc-ed. */
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char *errorInfo; /* Value of the errorInfo variable
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* (malloc-ed). */
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char *errorCode; /* Value of the errorCode variable
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* (malloc-ed). */
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struct BgError *nextPtr; /* Next in list of all pending error
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* reports for this interpreter, or NULL
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* for end of list. */
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} BgError;
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/*
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* One of the structures below is associated with the "tclBgError"
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* assoc data for each interpreter. It keeps track of the head and
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* tail of the list of pending background errors for the interpreter.
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*/
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typedef struct ErrAssocData {
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BgError *firstBgPtr; /* First in list of all background errors
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* waiting to be processed for this
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* interpreter (NULL if none). */
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BgError *lastBgPtr; /* Last in list of all background errors
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* waiting to be processed for this
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* interpreter (NULL if none). */
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} ErrAssocData;
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/*
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* For each exit handler created with a call to Tcl_CreateExitHandler
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* there is a structure of the following type:
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*/
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typedef struct ExitHandler {
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Tcl_ExitProc *proc; /* Procedure to call when process exits. */
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ClientData clientData; /* One word of information to pass to proc. */
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struct ExitHandler *nextPtr;/* Next in list of all exit handlers for
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* this application, or NULL for end of list. */
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} ExitHandler;
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static ExitHandler *firstExitPtr = NULL;
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/* First in list of all exit handlers for
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* application. */
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/*
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* The following variable is a "secret" indication to Tcl_Exit that
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* it should dump out the state of memory before exiting. If the
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* value is non-NULL, it gives the name of the file in which to
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* dump memory usage information.
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*/
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char *tclMemDumpFileName = NULL;
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/*
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* This variable is set to 1 when Tcl_Exit is called, and at the end of
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* its work, it is reset to 0. The variable is checked by TclInExit() to
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* allow different behavior for exit-time processing, e.g. in closing of
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* files and pipes.
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*/
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static int tclInExit = 0;
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/*
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* Prototypes for procedures referenced only in this file:
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*/
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static void BgErrorDeleteProc _ANSI_ARGS_((ClientData clientData,
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Tcl_Interp *interp));
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static void HandleBgErrors _ANSI_ARGS_((ClientData clientData));
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static char * VwaitVarProc _ANSI_ARGS_((ClientData clientData,
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Tcl_Interp *interp, char *name1, char *name2,
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int flags));
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/*
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*----------------------------------------------------------------------
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*
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* Tcl_BackgroundError --
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*
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* This procedure is invoked to handle errors that occur in Tcl
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* commands that are invoked in "background" (e.g. from event or
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* timer bindings).
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*
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* Results:
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* None.
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*
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* Side effects:
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* The command "bgerror" is invoked later as an idle handler to
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* process the error, passing it the error message. If that fails,
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* then an error message is output on stderr.
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*
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*----------------------------------------------------------------------
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*/
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void
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Tcl_BackgroundError(interp)
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Tcl_Interp *interp; /* Interpreter in which an error has
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* occurred. */
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{
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BgError *errPtr;
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char *errResult, *varValue;
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ErrAssocData *assocPtr;
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/*
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* The Tcl_AddErrorInfo call below (with an empty string) ensures that
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* errorInfo gets properly set. It's needed in cases where the error
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* came from a utility procedure like Tcl_GetVar instead of Tcl_Eval;
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* in these cases errorInfo still won't have been set when this
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* procedure is called.
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*/
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Tcl_AddErrorInfo(interp, "");
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errResult = TclGetStringFromObj(Tcl_GetObjResult(interp), (int *) NULL);
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errPtr = (BgError *) ckalloc(sizeof(BgError));
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errPtr->interp = interp;
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errPtr->errorMsg = (char *) ckalloc((unsigned) (strlen(errResult) + 1));
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strcpy(errPtr->errorMsg, errResult);
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varValue = Tcl_GetVar(interp, "errorInfo", TCL_GLOBAL_ONLY);
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if (varValue == NULL) {
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varValue = errPtr->errorMsg;
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}
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errPtr->errorInfo = (char *) ckalloc((unsigned) (strlen(varValue) + 1));
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strcpy(errPtr->errorInfo, varValue);
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varValue = Tcl_GetVar(interp, "errorCode", TCL_GLOBAL_ONLY);
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if (varValue == NULL) {
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varValue = "";
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}
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errPtr->errorCode = (char *) ckalloc((unsigned) (strlen(varValue) + 1));
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strcpy(errPtr->errorCode, varValue);
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errPtr->nextPtr = NULL;
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assocPtr = (ErrAssocData *) Tcl_GetAssocData(interp, "tclBgError",
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(Tcl_InterpDeleteProc **) NULL);
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if (assocPtr == NULL) {
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/*
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* This is the first time a background error has occurred in
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* this interpreter. Create associated data to keep track of
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* pending error reports.
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*/
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assocPtr = (ErrAssocData *) ckalloc(sizeof(ErrAssocData));
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assocPtr->firstBgPtr = NULL;
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assocPtr->lastBgPtr = NULL;
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Tcl_SetAssocData(interp, "tclBgError", BgErrorDeleteProc,
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(ClientData) assocPtr);
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}
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if (assocPtr->firstBgPtr == NULL) {
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assocPtr->firstBgPtr = errPtr;
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Tcl_DoWhenIdle(HandleBgErrors, (ClientData) assocPtr);
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} else {
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assocPtr->lastBgPtr->nextPtr = errPtr;
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}
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assocPtr->lastBgPtr = errPtr;
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Tcl_ResetResult(interp);
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}
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/*
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*----------------------------------------------------------------------
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*
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* HandleBgErrors --
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*
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* This procedure is invoked as an idle handler to process all of
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* the accumulated background errors.
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*
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* Results:
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* None.
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*
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* Side effects:
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* Depends on what actions "bgerror" takes for the errors.
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*
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*----------------------------------------------------------------------
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*/
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static void
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HandleBgErrors(clientData)
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ClientData clientData; /* Pointer to ErrAssocData structure. */
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{
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Tcl_Interp *interp;
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char *command;
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char *argv[2];
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int code;
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BgError *errPtr;
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ErrAssocData *assocPtr = (ErrAssocData *) clientData;
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Tcl_Channel errChannel;
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Tcl_Preserve((ClientData) assocPtr);
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while (assocPtr->firstBgPtr != NULL) {
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interp = assocPtr->firstBgPtr->interp;
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if (interp == NULL) {
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goto doneWithInterp;
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}
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/*
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* Restore important state variables to what they were at
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* the time the error occurred.
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*/
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Tcl_SetVar(interp, "errorInfo", assocPtr->firstBgPtr->errorInfo,
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TCL_GLOBAL_ONLY);
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Tcl_SetVar(interp, "errorCode", assocPtr->firstBgPtr->errorCode,
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TCL_GLOBAL_ONLY);
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/*
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* Create and invoke the bgerror command.
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*/
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argv[0] = "bgerror";
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argv[1] = assocPtr->firstBgPtr->errorMsg;
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command = Tcl_Merge(2, argv);
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Tcl_AllowExceptions(interp);
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Tcl_Preserve((ClientData) interp);
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code = Tcl_GlobalEval(interp, command);
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ckfree(command);
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if (code == TCL_ERROR) {
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/*
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* If the interpreter is safe, we look for a hidden command
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* named "bgerror" and call that with the error information.
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* Otherwise, simply ignore the error. The rationale is that
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* this could be an error caused by a malicious applet trying
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* to cause an infinite barrage of error messages. The hidden
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* "bgerror" command can be used by a security policy to
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* interpose on such attacks and e.g. kill the applet after a
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* few attempts.
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*/
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if (Tcl_IsSafe(interp)) {
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Tcl_HashTable *hTblPtr;
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Tcl_HashEntry *hPtr;
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hTblPtr = (Tcl_HashTable *) Tcl_GetAssocData(interp,
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"tclHiddenCmds", NULL);
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if (hTblPtr == (Tcl_HashTable *) NULL) {
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goto doneWithInterp;
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}
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hPtr = Tcl_FindHashEntry(hTblPtr, "bgerror");
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if (hPtr == (Tcl_HashEntry *) NULL) {
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goto doneWithInterp;
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}
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/*
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* OK, the hidden command "bgerror" exists, invoke it.
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*/
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argv[0] = "bgerror";
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argv[1] = ckalloc((unsigned)
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strlen(assocPtr->firstBgPtr->errorMsg));
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strcpy(argv[1], assocPtr->firstBgPtr->errorMsg);
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(void) TclInvoke(interp, 2, argv, TCL_INVOKE_HIDDEN);
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ckfree(argv[1]);
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goto doneWithInterp;
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}
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/*
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* We have to get the error output channel at the latest possible
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* time, because the eval (above) might have changed the channel.
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*/
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errChannel = Tcl_GetStdChannel(TCL_STDERR);
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if (errChannel != (Tcl_Channel) NULL) {
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if (strcmp(interp->result,
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"\"bgerror\" is an invalid command name or ambiguous abbreviation")
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== 0) {
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Tcl_Write(errChannel, assocPtr->firstBgPtr->errorInfo, -1);
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Tcl_Write(errChannel, "\n", -1);
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} else {
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Tcl_Write(errChannel,
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"bgerror failed to handle background error.\n",
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-1);
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Tcl_Write(errChannel, " Original error: ", -1);
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Tcl_Write(errChannel, assocPtr->firstBgPtr->errorMsg,
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-1);
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Tcl_Write(errChannel, "\n", -1);
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Tcl_Write(errChannel, " Error in bgerror: ", -1);
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Tcl_Write(errChannel, interp->result, -1);
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Tcl_Write(errChannel, "\n", -1);
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}
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Tcl_Flush(errChannel);
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}
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} else if (code == TCL_BREAK) {
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/*
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* Break means cancel any remaining error reports for this
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* interpreter.
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*/
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for (errPtr = assocPtr->firstBgPtr; errPtr != NULL;
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errPtr = errPtr->nextPtr) {
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if (errPtr->interp == interp) {
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errPtr->interp = NULL;
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}
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}
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}
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/*
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* Discard the command and the information about the error report.
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*/
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doneWithInterp:
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if (assocPtr->firstBgPtr) {
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ckfree(assocPtr->firstBgPtr->errorMsg);
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ckfree(assocPtr->firstBgPtr->errorInfo);
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ckfree(assocPtr->firstBgPtr->errorCode);
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errPtr = assocPtr->firstBgPtr->nextPtr;
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ckfree((char *) assocPtr->firstBgPtr);
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assocPtr->firstBgPtr = errPtr;
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}
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if (interp != NULL) {
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Tcl_Release((ClientData) interp);
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}
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}
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assocPtr->lastBgPtr = NULL;
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Tcl_Release((ClientData) assocPtr);
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}
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/*
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*----------------------------------------------------------------------
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*
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* BgErrorDeleteProc --
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*
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* This procedure is associated with the "tclBgError" assoc data
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* for an interpreter; it is invoked when the interpreter is
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* deleted in order to free the information assoicated with any
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* pending error reports.
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*
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* Results:
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* None.
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*
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* Side effects:
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* Background error information is freed: if there were any
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* pending error reports, they are cancelled.
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*
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*----------------------------------------------------------------------
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*/
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static void
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BgErrorDeleteProc(clientData, interp)
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ClientData clientData; /* Pointer to ErrAssocData structure. */
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Tcl_Interp *interp; /* Interpreter being deleted. */
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{
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ErrAssocData *assocPtr = (ErrAssocData *) clientData;
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BgError *errPtr;
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while (assocPtr->firstBgPtr != NULL) {
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errPtr = assocPtr->firstBgPtr;
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assocPtr->firstBgPtr = errPtr->nextPtr;
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ckfree(errPtr->errorMsg);
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ckfree(errPtr->errorInfo);
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ckfree(errPtr->errorCode);
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ckfree((char *) errPtr);
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}
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Tcl_CancelIdleCall(HandleBgErrors, (ClientData) assocPtr);
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Tcl_EventuallyFree((ClientData) assocPtr, TCL_DYNAMIC);
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}
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/*
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*----------------------------------------------------------------------
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*
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* Tcl_CreateExitHandler --
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*
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* Arrange for a given procedure to be invoked just before the
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* application exits.
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*
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* Results:
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* None.
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*
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* Side effects:
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* Proc will be invoked with clientData as argument when the
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* application exits.
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*
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*----------------------------------------------------------------------
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*/
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void
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Tcl_CreateExitHandler(proc, clientData)
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Tcl_ExitProc *proc; /* Procedure to invoke. */
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ClientData clientData; /* Arbitrary value to pass to proc. */
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{
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ExitHandler *exitPtr;
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exitPtr = (ExitHandler *) ckalloc(sizeof(ExitHandler));
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exitPtr->proc = proc;
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exitPtr->clientData = clientData;
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exitPtr->nextPtr = firstExitPtr;
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firstExitPtr = exitPtr;
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}
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/*
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*----------------------------------------------------------------------
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*
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* Tcl_DeleteExitHandler --
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*
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* This procedure cancels an existing exit handler matching proc
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* and clientData, if such a handler exits.
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*
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* Results:
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* None.
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*
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* Side effects:
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* If there is an exit handler corresponding to proc and clientData
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* then it is cancelled; if no such handler exists then nothing
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* happens.
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*
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*----------------------------------------------------------------------
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*/
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void
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Tcl_DeleteExitHandler(proc, clientData)
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Tcl_ExitProc *proc; /* Procedure that was previously registered. */
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ClientData clientData; /* Arbitrary value to pass to proc. */
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{
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ExitHandler *exitPtr, *prevPtr;
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for (prevPtr = NULL, exitPtr = firstExitPtr; exitPtr != NULL;
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prevPtr = exitPtr, exitPtr = exitPtr->nextPtr) {
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if ((exitPtr->proc == proc)
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&& (exitPtr->clientData == clientData)) {
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if (prevPtr == NULL) {
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firstExitPtr = exitPtr->nextPtr;
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} else {
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prevPtr->nextPtr = exitPtr->nextPtr;
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}
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ckfree((char *) exitPtr);
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return;
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}
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}
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}
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/*
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*----------------------------------------------------------------------
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*
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* Tcl_Exit --
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*
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* This procedure is called to terminate the application.
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*
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* Results:
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* None.
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*
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* Side effects:
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* All existing exit handlers are invoked, then the application
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* ends.
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*
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*----------------------------------------------------------------------
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*/
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void
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Tcl_Exit(status)
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int status; /* Exit status for application; typically
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* 0 for normal return, 1 for error return. */
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{
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Tcl_Finalize();
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#ifdef TCL_MEM_DEBUG
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if (tclMemDumpFileName != NULL) {
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Tcl_DumpActiveMemory(tclMemDumpFileName);
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}
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#endif
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TclPlatformExit(status);
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}
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/*
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*----------------------------------------------------------------------
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*
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* Tcl_Finalize --
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*
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* Runs the exit handlers to allow Tcl to clean up its state prior
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* to being unloaded. Called by Tcl_Exit and when Tcl was dynamically
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* loaded and is now being unloaded.
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*
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* Results:
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* None.
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*
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* Side effects:
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* Whatever the exit handlers do. Also frees up storage associated
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* with the Tcl object type table.
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*
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*----------------------------------------------------------------------
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*/
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void
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Tcl_Finalize()
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{
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ExitHandler *exitPtr;
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/*
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* Invoke exit handler first.
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*/
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tclInExit = 1;
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for (exitPtr = firstExitPtr; exitPtr != NULL; exitPtr = firstExitPtr) {
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/*
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* Be careful to remove the handler from the list before invoking
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* its callback. This protects us against double-freeing if the
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* callback should call Tcl_DeleteExitHandler on itself.
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*/
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firstExitPtr = exitPtr->nextPtr;
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(*exitPtr->proc)(exitPtr->clientData);
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ckfree((char *) exitPtr);
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}
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/*
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* Now finalize the Tcl execution environment. Note that this must be done
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* after the exit handlers, because there are order dependencies.
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*/
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TclFinalizeCompExecEnv();
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TclFinalizeEnvironment();
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firstExitPtr = NULL;
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tclInExit = 0;
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}
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/*
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*----------------------------------------------------------------------
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*
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* TclInExit --
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*
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* Determines if we are in the middle of exit-time cleanup.
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*
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||
* Results:
|
||
* If we are in the middle of exiting, 1, otherwise 0.
|
||
*
|
||
* Side effects:
|
||
* None.
|
||
*
|
||
*----------------------------------------------------------------------
|
||
*/
|
||
|
||
int
|
||
TclInExit()
|
||
{
|
||
return tclInExit;
|
||
}
|
||
|
||
/*
|
||
*----------------------------------------------------------------------
|
||
*
|
||
* Tcl_VwaitCmd --
|
||
*
|
||
* This procedure is invoked to process the "vwait" Tcl command.
|
||
* See the user documentation for details on what it does.
|
||
*
|
||
* Results:
|
||
* A standard Tcl result.
|
||
*
|
||
* Side effects:
|
||
* See the user documentation.
|
||
*
|
||
*----------------------------------------------------------------------
|
||
*/
|
||
|
||
/* ARGSUSED */
|
||
int
|
||
Tcl_VwaitCmd(clientData, interp, argc, argv)
|
||
ClientData clientData; /* Not used. */
|
||
Tcl_Interp *interp; /* Current interpreter. */
|
||
int argc; /* Number of arguments. */
|
||
char **argv; /* Argument strings. */
|
||
{
|
||
int done, foundEvent;
|
||
|
||
if (argc != 2) {
|
||
Tcl_AppendResult(interp, "wrong # args: should be \"",
|
||
argv[0], " name\"", (char *) NULL);
|
||
return TCL_ERROR;
|
||
}
|
||
if (Tcl_TraceVar(interp, argv[1],
|
||
TCL_GLOBAL_ONLY|TCL_TRACE_WRITES|TCL_TRACE_UNSETS,
|
||
VwaitVarProc, (ClientData) &done) != TCL_OK) {
|
||
return TCL_ERROR;
|
||
};
|
||
done = 0;
|
||
foundEvent = 1;
|
||
while (!done && foundEvent) {
|
||
foundEvent = Tcl_DoOneEvent(TCL_ALL_EVENTS);
|
||
}
|
||
Tcl_UntraceVar(interp, argv[1],
|
||
TCL_GLOBAL_ONLY|TCL_TRACE_WRITES|TCL_TRACE_UNSETS,
|
||
VwaitVarProc, (ClientData) &done);
|
||
|
||
/*
|
||
* Clear out the interpreter's result, since it may have been set
|
||
* by event handlers.
|
||
*/
|
||
|
||
Tcl_ResetResult(interp);
|
||
if (!foundEvent) {
|
||
Tcl_AppendResult(interp, "can't wait for variable \"", argv[1],
|
||
"\": would wait forever", (char *) NULL);
|
||
return TCL_ERROR;
|
||
}
|
||
return TCL_OK;
|
||
}
|
||
|
||
/* ARGSUSED */
|
||
static char *
|
||
VwaitVarProc(clientData, interp, name1, name2, flags)
|
||
ClientData clientData; /* Pointer to integer to set to 1. */
|
||
Tcl_Interp *interp; /* Interpreter containing variable. */
|
||
char *name1; /* Name of variable. */
|
||
char *name2; /* Second part of variable name. */
|
||
int flags; /* Information about what happened. */
|
||
{
|
||
int *donePtr = (int *) clientData;
|
||
|
||
*donePtr = 1;
|
||
return (char *) NULL;
|
||
}
|
||
|
||
/*
|
||
*----------------------------------------------------------------------
|
||
*
|
||
* Tcl_UpdateCmd --
|
||
*
|
||
* This procedure is invoked to process the "update" Tcl command.
|
||
* See the user documentation for details on what it does.
|
||
*
|
||
* Results:
|
||
* A standard Tcl result.
|
||
*
|
||
* Side effects:
|
||
* See the user documentation.
|
||
*
|
||
*----------------------------------------------------------------------
|
||
*/
|
||
|
||
/* ARGSUSED */
|
||
int
|
||
Tcl_UpdateCmd(clientData, interp, argc, argv)
|
||
ClientData clientData; /* Not used. */
|
||
Tcl_Interp *interp; /* Current interpreter. */
|
||
int argc; /* Number of arguments. */
|
||
char **argv; /* Argument strings. */
|
||
{
|
||
int flags;
|
||
|
||
if (argc == 1) {
|
||
flags = TCL_ALL_EVENTS|TCL_DONT_WAIT;
|
||
} else if (argc == 2) {
|
||
if (strncmp(argv[1], "idletasks", strlen(argv[1])) != 0) {
|
||
Tcl_AppendResult(interp, "bad option \"", argv[1],
|
||
"\": must be idletasks", (char *) NULL);
|
||
return TCL_ERROR;
|
||
}
|
||
flags = TCL_WINDOW_EVENTS|TCL_IDLE_EVENTS|TCL_DONT_WAIT;
|
||
} else {
|
||
Tcl_AppendResult(interp, "wrong # args: should be \"",
|
||
argv[0], " ?idletasks?\"", (char *) NULL);
|
||
return TCL_ERROR;
|
||
}
|
||
|
||
while (Tcl_DoOneEvent(flags) != 0) {
|
||
/* Empty loop body */
|
||
}
|
||
|
||
/*
|
||
* Must clear the interpreter's result because event handlers could
|
||
* have executed commands.
|
||
*/
|
||
|
||
Tcl_ResetResult(interp);
|
||
return TCL_OK;
|
||
}
|