1USB_ALTNUM_TO_ALTSET(9) USB Core APIs USB_ALTNUM_TO_ALTSET(9)
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6 usb_altnum_to_altsetting - get the altsetting structure with a given
7 alternate setting number.
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10 struct usb_host_interface *
11 usb_altnum_to_altsetting(const struct usb_interface * intf,
12 unsigned int altnum);
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15 intf
16 the interface containing the altsetting in question
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18 altnum
19 the desired alternate setting number
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22 This searches the altsetting array of the specified interface for an
23 entry with the correct bAlternateSetting value and returns a pointer to
24 that entry, or null.
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26 Note that altsettings need not be stored sequentially by number, so it
27 would be incorrect to assume that the first altsetting entry in the
28 array corresponds to altsetting zero. This routine helps device drivers
29 avoid such mistakes.
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31 Don't call this function unless you are bound to the intf interface or
32 you have locked the device!
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35Kernel Hackers Manual 2.6. November 2011 USB_ALTNUM_TO_ALTSET(9)