usb_descriptor_fillbuf — fill buffer with descriptors
int usb_descriptor_fillbuf
(void * buf, unsigned buflen, const struct usb_descriptor_header ** src);
Buffer to be filled
Size of buf
Array of descriptor pointers, terminated by null pointer.
Copies descriptors into the buffer, returning the length or a negative error code if they can't all be copied. Useful when assembling descriptors for an associated set of interfaces used as part of configuring a composite device; or in other cases where sets of descriptors need to be marshaled.