USB_ATTACH_SETUP macros question

[Tofig Suleymanov]

> On Thu, Aug 17, 2006 at 05:10:02PM +0500, Tofig Suleymanov wrote:
>> Hello hackers,
>>
>> is there anybody to explain why do we have infinite loop inside of
>> USB_ATTACH_SETUP macros inside of usb_port.h ? How does his loop gets
>> escaped when we use it in some usb driver ?
>>
>> #define USB_ATTACH_SETUP \
>>         do { \
>>                 sc->sc_dev = self; \
>>                 device_set_desc_copy(self, devinfo); \
>>                 device_printf(self, "%s\n", devinfo); \
>>         } while (0);
>>
>> Thank you  !
>>
>> Tofig Suleymanov
>>
> This isn't an infinite loop, in fact it will never be executed.
>
> Baldur
>

Made a little test which shows that this code is going to be executed only
once.How did i miss that :) Now the other question comes next:
Why don not we use just:
#define USB_ATTACH_SETUP \
sc->sc_dev = self; \
device_set_desc_copy(self, devinfo); \
device_printf(self, "%s\n", devinfo);

?
Thank you,
Tofig Suleymanov