dynamic array size calculation

config.h:
=========
#define STRING                0x03
#define USB_MANUFACTURER_NAME {'T'<<8, 'E'<<8, 'S'<<8, 'T'<<8, '1'<<8}
#define USB_MN_LENGTH         5  //  (sizeof(USB_MANUFACTURER_NAME) >> 1)

usb_enum.h:
=======
struct usb_st_manufacturer
{
  Uchar  bLength;               /* size of this descriptor in bytes */
  Uchar  bDescriptorType;       /* STRING descriptor type */
  Uint16 wstring[USB_MN_LENGTH];/* unicode characters */
};

usb_enum.c:
=======

code struct usb_st_manufacturer usb_manufacturer =
{ sizeof(usb_manufacturer),  STRING, USB_MANUFACTURER_NAME };

I want to change the Unicode string USB_MANUFACTURER_NAME without calculate the new length USB_MN_LENGTH with counting chars. How do i do this?

I get C141 error.

Thanks in advance.