const struct ClockCommand *clockCmdPtr;
    char cmdName[50];		/* Buffer large enough to hold the string
				 *::tcl::clock::GetJulianDayFromEraYearMonthDay
				 * plus a terminating NUL. */
    Command *cmdPtr;
    ClockClientData *data;

    static bool initialized = false;	/* global clock engine initialized (in process) */
    /*
     * Register handler to finalize clock on exit.
     */
    if (!initialized) {
	Tcl_CreateExitHandler(ClockFinalize, NULL);
	initialized = true;
    }

    /*
     * Safe interps get [::clock] as alias to a parent, so do not need their
     * own copies of the support routines.
     */

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

static Tcl_Obj *
NormTimezoneObj(
    ClockClientData *dataPtr,	/* Client data containing literal pool */
    Tcl_Obj *timezoneObj,	/* Name of zone to find */
    bool *loaded)		/* Used to recognized TZ was loaded */
{
    const char *tz;

    *loaded = true;
    if (timezoneObj == dataPtr->lastSetupTimeZoneUnnorm
	    && dataPtr->lastSetupTimeZone != NULL) {
	return dataPtr->lastSetupTimeZone;
    }
    if (timezoneObj == dataPtr->prevSetupTimeZoneUnnorm
	    && dataPtr->prevSetupTimeZone != NULL) {
	return dataPtr->prevSetupTimeZone;

    if (dataPtr->systemTimeZone != NULL
	    && strcmp(tz, TclGetString(dataPtr->systemTimeZone)) == 0) {
	return dataPtr->systemTimeZone;
    }
    if (strcmp(tz, Literals[LIT_GMT]) == 0) {
	TclSetObjRef(dataPtr->gmtSetupTimeZoneUnnorm, timezoneObj);
	if (dataPtr->gmtSetupTimeZone == NULL) {
	    *loaded = false;
	}
	return dataPtr->literals[LIT_GMT];
    }
    /* unknown/unloaded tz - recache/revalidate later as last-setup if needed */
    *loaded = false;
    return timezoneObj;
}

/*
 *----------------------------------------------------------------------
 *
 * ClockGetSystemLocale --

		    && dataPtr->lastTZEpoch == lastTZEpoch) {
		Tcl_SetObjResult(interp, dataPtr->systemTimeZone);
	    }
	    break;
	}
	case CLOCK_SETUP_TZ:
	    if (i < objc) {
		bool loaded;
		Tcl_Obj *timezoneObj = NormTimezoneObj(dataPtr, objv[i], &loaded);

		if (!loaded) {
		    TimezoneLoaded(dataPtr, timezoneObj, objv[i]);
		}
		Tcl_SetObjResult(interp, timezoneObj);
	    } else if (i + 1 >= objc && dataPtr->lastSetupTimeZone != NULL) {

Tcl_Obj *
ClockSetupTimeZone(
    ClockClientData *dataPtr,	/* Pointer to literal pool, etc. */
    Tcl_Interp *interp,		/* Tcl interpreter */
    Tcl_Obj *timezoneObj)
{



    /* if cached (if already setup this one) */
    if (timezoneObj == dataPtr->literals[LIT_GMT]
	    && dataPtr->gmtSetupTZData != NULL) {
	return timezoneObj;
    }
    if ((timezoneObj == dataPtr->lastSetupTimeZone
	    || timezoneObj == dataPtr->lastSetupTimeZoneUnnorm)
	    && dataPtr->lastSetupTimeZone != NULL) {
	return dataPtr->lastSetupTimeZone;
    }
    if ((timezoneObj == dataPtr->prevSetupTimeZone
	    || timezoneObj == dataPtr->prevSetupTimeZoneUnnorm)
	    && dataPtr->prevSetupTimeZone != NULL) {
	return dataPtr->prevSetupTimeZone;
    }

    /* differentiate normalized (last, GMT and system) zones, because used often and already set */
    bool loaded;
    Tcl_Obj *normTzObj = NormTimezoneObj(dataPtr, timezoneObj, &loaded);
    /* if loaded (setup already called for this TZ) */
    if (loaded) {
	return normTzObj;
    }

    /* before setup just take a look in TZData variable */
    if (Tcl_ObjGetVar2(interp, dataPtr->literals[LIT_TZDATA], timezoneObj, 0)) {

    Tcl_Obj *const *objv)	/* Parameter vector */
{
    ClockClientData *dataPtr = (ClockClientData *)clientData;
    Tcl_Obj *secondsObj;
    Tcl_Obj *dict;
    int changeover;
    TclDateFields fields;
    bool created = false;
    int status;

    fields.tzName = NULL;
    /*
     * Check params and convert time.
     */

    /*
     * Copy-on-write; set the 'seconds' field in the dictionary and place the
     * modified dictionary in the interpreter result.
     */

    if (Tcl_IsShared(dict)) {
	dict = Tcl_DuplicateObj(dict);
	created = true;
	Tcl_IncrRefCount(dict);
    }
    status = Tcl_DictObjPut(interp, dict, dataPtr->literals[LIT_SECONDS],
	    Tcl_NewWideIntObj(fields.seconds));
    if (status == TCL_OK) {
	Tcl_SetObjResult(interp, dict);
    }

 */

static int
FetchEraField(
    Tcl_Interp *interp,
    Tcl_Obj *dict,
    Tcl_Obj *key,
    bool *storePtr)
{
    Tcl_Obj *value = NULL;

    if (Tcl_DictObjGet(interp, dict, key, &value) != TCL_OK) {
	return TCL_ERROR;
    }
    if (value == NULL) {

    int objc,			/* Parameter count */
    Tcl_Obj *const *objv)	/* Parameter vector */
{
    TclDateFields fields;
    ClockClientData *data = (ClockClientData *)clientData;
    Tcl_Obj *const *lit = data->literals;
    int changeover;
    bool isBce = false;

    fields.tzName = NULL;

    /*
     * Check params.
     */

    GetJulianDayFromEraYearMonthDay(&fields, changeover);

    /*
     * Store Julian day in the dictionary - copy on write.
     */

    bool copied = false;
    if (Tcl_IsShared(dict)) {
	dict = Tcl_DuplicateObj(dict);
	Tcl_IncrRefCount(dict);
	copied = true;
    }
    int status = Tcl_DictObjPut(interp, dict, lit[LIT_JULIANDAY],
	    Tcl_NewWideIntObj(fields.julianDay));
    if (status == TCL_OK) {
	Tcl_SetObjResult(interp, dict);
    }
    if (copied) {

    int objc,			/* Parameter count */
    Tcl_Obj *const *objv)	/* Parameter vector */
{
    TclDateFields fields;
    Tcl_Obj *dict;
    ClockClientData *data = (ClockClientData *)clientData;
    Tcl_Obj *const *lit = data->literals;
    int changeover, status;
    bool copied = false, isBce = false;

    fields.tzName = NULL;

    /*
     * Check params.
     */

    /*
     * Store Julian day in the dictionary - copy on write.
     */

    if (Tcl_IsShared(dict)) {
	dict = Tcl_DuplicateObj(dict);
	Tcl_IncrRefCount(dict);
	copied = true;
    }
    status = Tcl_DictObjPut(interp, dict, lit[LIT_JULIANDAY],
	    Tcl_NewWideIntObj(fields.julianDay));
    if (status == TCL_OK) {
	Tcl_SetObjResult(interp, dict);
    }
    if (copied) {

	return TCL_ERROR;
    }

    /*
     * Fill in the date in 'fields' and use it to derive Julian Day.
     */

    fields->isBce = false;
    fields->year = timeVal->tm_year + 1900;
    fields->month = timeVal->tm_mon + 1;
    fields->dayOfMonth = timeVal->tm_mday;
    GetJulianDayFromEraYearMonthDay(fields, changeover);

    /*
     * Convert that value to seconds.

    Tcl_WideInt n;

    if (jday >= changeover) {
	/*
	 * Gregorian calendar.
	 */

	fields->gregorian = true;
	year = 1;

	/*
	 * n = Number of 400-year cycles since 1 January, 1 CE in the
	 * proleptic Gregorian calendar. day = remaining days.
	 */

	}
	year += 100 * n;
    } else {
	/*
	 * Julian calendar.
	 */

	fields->gregorian = false;
	year = 1;
	day = jday - JDAY_1_JAN_1_CE_JULIAN;
    }

    /*
     * n = number of 4-year cycles; days = remaining days.
     */

    year += n;

    /*
     * store era/year/day back into fields.
     */

    if (year <= 0) {
	fields->isBce = true;
	fields->year = 1 - year;
    } else {
	fields->isBce = false;
	fields->year = year;
    }
    fields->dayOfYear = day + 1;
}

/*
 *----------------------------------------------------------------------

    month = r + 1;
    ym1 = year - 1;

    /*
     * Adjust the year after reducing the month.
     */

    fields->gregorian = true;
    if (year < 1) {
	fields->isBce = true;
	fields->year = 1 - year;
    } else {
	fields->isBce = false;
	fields->year = year;
    }

    /*
     * Try an initial conversion in the Gregorian calendar.
     */

    /*
     * If the resulting date is before the Gregorian changeover, convert in
     * the Julian calendar instead.
     */

    if (fields->julianDay < changeover) {
	fields->gregorian = false;
	fields->julianDay = JDAY_1_JAN_1_CE_JULIAN - 1
		+ fields->dayOfMonth
		+ daysInPriorMonths[year%4 == 0][month - 1]
		+ (365 * ym1)
		+ ym1o4;
    }
}

    } else {
	year = fields->year;
    }

    ym1 = year - 1;

    /* Try the Gregorian calendar first. */
    fields->gregorian = true;
    fields->julianDay =
	    1721425
	    + fields->dayOfYear
	    + (365 * ym1)
	    + (ym1 / 4)
	    - (ym1 / 100)
	    + (ym1 / 400);

    /* If the date is before the Gregorian change, use the Julian calendar. */

    if (fields->julianDay < changeover) {
	fields->gregorian = false;
	fields->julianDay =
		1721423
		+ fields->dayOfYear
		+ (365 * ym1)
		+ (ym1 / 4);
    }
}

    Tcl_Size objc,		/* Parameter count */
    Tcl_Obj *const objv[],	/* Parameter vector */
    ClockOperation operation,	/* What operation are we doing: format, scan, add */
    const char *syntax)		/* Syntax of the current command */
{
    Tcl_Interp *interp = opts->interp;
    ClockClientData *dataPtr = opts->dataPtr;
    bool gmtFlag = false;
    static const char *const options[] = {
	"-base", "-format", "-gmt", "-locale", "-timezone", "-validate", NULL
    };
    enum optionInd {
	CLC_ARGS_BASE, CLC_ARGS_FORMAT, CLC_ARGS_GMT, CLC_ARGS_LOCALE,
	CLC_ARGS_TIMEZONE, CLC_ARGS_VALIDATE
    };
    int optionIndex;		/* Index of an option. */
    int saw = 0;		/* Bit flags: 1 if option was seen already. */
    Tcl_Size i, baseIdx;
    Tcl_WideInt baseVal;	/* Base time, expressed in seconds from the Epoch */

    if (operation == CLC_OP_SCN) {
	/* default flags (from configure) */
	opts->flags |= dataPtr->defFlags & CLF_VALIDATE;
    } else {

	case CLC_ARGS_BASE:
	    opts->baseObj = objv[(baseIdx = i + 1)];
	    break;
	case CLC_ARGS_VALIDATE:
	    if (operation != CLC_OP_SCN) {
		goto badOptionMsg;
	    } else {
		bool val;

		if (Tcl_GetBooleanFromObj(interp, objv[i + 1], &val) != TCL_OK) {
		    return TCL_ERROR;
		}
		if (val) {
		    opts->flags |= CLF_VALIDATE;
		} else {

    Tcl_Obj *const objv[])	/* Parameter values */
{
    ClockClientData *dataPtr = (ClockClientData *)clientData;
    static const char *syntax = "clock format clockval|now "
	    "?-format string? "
	    "?-gmt boolean? "
	    "?-locale LOCALE? ?-timezone ZONE?";

    ClockFmtScnCmdArgs opts;	/* Format, locale, timezone and base */
    DateFormat dateFmt;		/* Common structure used for formatting */

    /* even number of arguments */
    if ((objc & 1) == 1) {
	Tcl_WrongNumArgs(interp, 0, objv, syntax);
	TclSetErrorCode(interp, "CLOCK", "wrongNumArgs");
	return TCL_ERROR;
    }

    memset(&dateFmt, 0, sizeof(dateFmt));

    /*
     * Extract values for the keywords.
     */

    ClockInitFmtScnArgs(dataPtr, interp, &opts);
    int ret = ClockParseFmtScnArgs(&opts, &dateFmt.date, objc, objv,
	    CLC_OP_FMT, "-format, -gmt, -locale, or -timezone");
    if (ret != TCL_OK) {
	goto done;
    }

    /* Default format */
    if (opts.formatObj == NULL) {

{
    ClockClientData *dataPtr = (ClockClientData *)clientData;
    static const char *syntax = "clock scan string "
	    "?-base seconds? "
	    "?-format string? "
	    "?-gmt boolean? "
	    "?-locale LOCALE? ?-timezone ZONE? ?-validate boolean?";

    ClockFmtScnCmdArgs opts;	/* Format, locale, timezone and base */
    DateInfo yy;		/* Common structure used for parsing */
    DateInfo *info = &yy;

    /* even number of arguments */
    if ((objc & 1) == 1) {
	Tcl_WrongNumArgs(interp, 0, objv, syntax);
	TclSetErrorCode(interp, "CLOCK", "wrongNumArgs");
	return TCL_ERROR;
    }

    ClockInitDateInfo(&yy);

    /*
     * Extract values for the keywords.
     */

    ClockInitFmtScnArgs(dataPtr, interp, &opts);
    int ret = ClockParseFmtScnArgs(&opts, &yy.date, objc, objv,
	    CLC_OP_SCN, "-base, -format, -gmt, -locale, -timezone or -validate");
    if (ret != TCL_OK) {
	goto done;
    }

    /* seconds are in localSeconds (relative base date), so reset time here */
    yyHour = yyMinutes = yySeconds = yySecondOfDay = 0;

    if (info->flags & CLF_YEAR) {
	if (yyYear < 100) {
	    if (yyYear >= dataPtr->yearOfCenturySwitch) {
		yyYear -= 100;
	    }
	    yyYear += dataPtr->currentYearCentury;
	}
	yydate.isBce = false;
	info->flags |= CLF_ASSEMBLE_JULIANDAY|CLF_ASSEMBLE_SECONDS;
    }

    /*
     * If the caller supplied a time zone in the string, make it into a time
     * zone indicator of +-hhmm and setup this time zone.
     */

	/* if needed assemble julianDay now */
	if (info->flags & CLF_ASSEMBLE_JULIANDAY) {
	    GetJulianDayFromEraYearMonthDay(&yydate, GREGORIAN_CHANGE_DATE);
	    info->flags &= ~CLF_ASSEMBLE_JULIANDAY;
	}

	yydate.isBce = false;
	yydate.julianDay = WeekdayOnOrBefore(yyDayOfWeek, yydate.julianDay + 6)
		+ 7 * yyDayOrdinal;
	if (yyDayOrdinal > 0) {
	    yydate.julianDay -= 7;
	}
	info->flags |= CLF_ASSEMBLE_DATE|CLF_ASSEMBLE_SECONDS;
    }

    int objc,			/* Parameter count */
    Tcl_Obj *const objv[])	/* Parameter values */
{
    static const char *syntax = "clock add clockval|now ?number units?..."
	    "?-gmt boolean? "
	    "?-locale LOCALE? ?-timezone ZONE?";
    ClockClientData *dataPtr = (ClockClientData *)clientData;

    ClockFmtScnCmdArgs opts;	/* Format, locale, timezone and base */
    DateInfo yy;		/* Common structure used for parsing */
    DateInfo *info = &yy;

    /* add "week" to units also (because otherwise ambiguous) */
    static const char *const units[] = {
	"years",	"months",	    "week",	    "weeks",

    ClockInitDateInfo(&yy);

    /*
     * Extract values for the keywords.
     */

    ClockInitFmtScnArgs(dataPtr, interp, &opts);
    int ret = ClockParseFmtScnArgs(&opts, &yy.date, objc, objv,
	    CLC_OP_ADD, "-gmt, -locale, or -timezone");
    if (ret != TCL_OK) {
	goto done;
    }

    /* time together as seconds of the day */
    yySecondOfDay = yydate.localSeconds % SECONDS_PER_DAY;

	Tcl_Obj *returnOpts;
	Tcl_Obj *objResult;
	Tcl_Obj *errorStack;
	int resetErrorStack;
    } InterpState;

    Interp *iPtr = (Interp *)interp;
    int flags = 0;


    if (objc == 1) {
	/* wrong # args : */
	return Tcl_CatchObjCmd(NULL, interp, objc, objv);
    }

    InterpState *statePtr = (InterpState *)Tcl_SaveInterpState(interp, 0);
    if (!statePtr->errorInfo) {
	/* todo: avoid traced get of errorInfo here */
	TclInitObjRef(statePtr->errorInfo,
		Tcl_ObjGetVar2(interp, iPtr->eiVar, NULL, 0));
	flags |= ERR_LEGACY_COPY;
    }
    if (!statePtr->errorCode) {
	/* todo: avoid traced get of errorCode here */
	TclInitObjRef(statePtr->errorCode,
		Tcl_ObjGetVar2(interp, iPtr->ecVar, NULL, 0));
	flags |= ERR_LEGACY_COPY;
    }

    /* original catch */
    int ret = Tcl_CatchObjCmd(NULL, interp, objc, objv);

    if (ret == TCL_ERROR) {
	Tcl_DiscardInterpState((Tcl_InterpState)statePtr);
	return TCL_ERROR;
    }
    /* overwrite result in state with catch result */
    TclSetObjRef(statePtr->objResult, Tcl_GetObjResult(interp));