PATHHardware Documentation > USB Devices > Mac OS USB DDK API Reference

USBOpenPipe

The USBOpenPipe function sets up a connection to a specified endpoint and returns a pipe reference ( USBPipeRef ) to this connection. This reference is passed to the USB on all subsequent data transactions for this pipe. See the USBControlRequest for information about performing data transactions.

Required fields in the USBPB parameter block for the USBOpenPipe function are

--> pbLength

Length of parameter block

--> pbVersion

Parameter block version number

--> usbCompletion

The completion routine

--> usbRefcon

General-purpose value passed back to the completion routine

<--> usbReference

--> Device reference of device to be opened
<-- Reference to the pipe opened

--> usbClassType

Type of endpoint ( kUSBBulk , kUSBInterrupt , kUSBIsoc )

--> usbOther

The endpoint number within the device to open a pipe to, the endpoint number from the endpoint descriptor

--> usbWValue

maxPacketSize

--> usbFlags

Indicates whether the direction of the endpoint to be opened is in or out ( kUSBIn , kUSBOut )

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