if ((ch < 0x80) && isdigit(UCHAR(ch))) {	/* INTL: "C" locale. */
	    /*
	     * Check for an XPG3-style %n$ specification. Note: there must
	     * not be a mixture of XPG3 specs and non-XPG3 specs in the same
	     * format string.
	     */

	    /* assert(value is >= 0) because of the isdigit() check above */
	    long longVal = strtoul(format-1, &end, 10);	/* INTL: "C" locale. */
	    unsigned long long ull = strtoull(format-1, &end, 10);	/* INTL: "C" locale. */
	    if (*end != '$') {
		goto notXpg;
	    }
	    /* assert(longVal >= 0) because of the isdigit() check above */
	    format = end+1;
	    format += TclUtfToUniChar(format, &ch);
	    gotXpg = 1;
	    if (gotSequential) {
		goto mixedXPG;
	    }
	    objIndex = longVal - 1;
	    /* INT_MAX because 9.0 does not support more than INT_MAX-1 args */
	    if ((objIndex < 0) || objIndex >= INT_MAX ||
		(numVars && (objIndex >= numVars))) {
	    /* >=INT_MAX because 9.0 does not support more than INT_MAX-1 args */
	    if (ull == 0 || ull >= INT_MAX) {
		goto badIndex;
	    }
	    objIndex = (int) ull - 1;
	    if (numVars && (objIndex >= numVars)) {
		goto badIndex;
	    }
	    else if (numVars == 0) {
		/*
		 * In the case where no vars are specified, the user can
		 * specify %9999$ legally, so we have to consider special
		 * rules for growing the assign array. 'longVal' is guaranteed
		 * to be > 0.
		 * rules for growing the assign array. 'ull' is guaranteed
		 * to be > 0 and < INT_MAX as per checks above.
		 */
		xpgSize = (xpgSize > longVal) ? xpgSize : longVal;
		xpgSize = (xpgSize > (int)ull) ? xpgSize : (int)ull;
	    }
	    goto xpgCheckDone;
	}

    notXpg:
	gotSequential = 1;
	if (gotXpg) {