Provided by: linux-doc-2.6.15_2.6.15-23.39_all bug

NAME

       usb_ifnum_to_if  -  get  the  interface  object  with a given interface
       number

SYNOPSIS

       struct usb_interface * usb_ifnum_to_if  (struct usb_device * dev,
                                                   unsigned ifnum);

ARGUMENTS

       dev    the device whose current configuration is considered

       ifnum  the desired interface

DESCRIPTION

       This walks the device descriptor for the currently active configuration
       and returns a pointer to the interface with that  particular  interface
       number, or null.

       Note   that  configuration  descriptors  are  not  required  to  assign
       interface numbers sequentially, so that it would be incorrect to assume
       that  the  first  interface in that descriptor corresponds to interface
       zero. This routine helps device drivers avoid such  mistakes.  However,
       you  should  make  sure  that you do the right thing with any alternate
       settings available for this interfaces.

       Don’t call this function unless you are bound to one of the  interfaces
       on this device or you have locked the device!