usb_ifnum_to_if(9) - phpMan
USB_IFNUM_TO_IF(9) USB Core APIs USB_IFNUM_TO_IF(9)
usb_ifnum_to_if - get the interface object with a given interface number
struct usb_interface * usb_ifnum_to_if(const struct usb_device * dev, unsigned ifnum);
the device whose current configuration is considered
the desired interface
This walks the device descriptor for the currently active configuration to find the
interface object with the particular interface number.
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!
A pointer to the interface that has ifnum as interface number, if found. NULL otherwise.
Kernel Hackers Manual 4.8. January 2017 USB_IFNUM_TO_IF(9)