* minus 1 byte. */
    unsigned char bytes[1];	/* The array of bytes. The actual size of this
				 * field depends on the 'allocated' field
				 * above. */
} ByteArray;

#define BYTEARRAY_SIZE(len) \
		((unsigned) (TclOffset(ByteArray, bytes) + (len)))
		(offsetof(ByteArray, bytes) + (len))
#define GET_BYTEARRAY(irPtr) ((ByteArray *) (irPtr)->twoPtrValue.ptr1)
#define SET_BYTEARRAY(irPtr, baPtr) \
		(irPtr)->twoPtrValue.ptr1 = (void *) (baPtr)

int
TclIsPureByteArray(
    Tcl_Obj * objPtr)