USBFindNextPipe

The USBFindNextPipe function can be used to either find a specific pipe, as specified by the direction in the usbFlags field and type in the usbClassType field, or to search through the available pipes.

OSStatus USBFindNextPipe(USBPB *pb);

Required fields required the USBPB parameter block for the USBFindNextPipe 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

--> Interface or pipe reference <-- Pipe reference

-- usbBuffer

Should be set to 0 (0 returned); reserved in this call

-- usbActCount

Should be set to 0 (0 returned); reserved in this call

-- usbReqCount

Should be set to 0 (0 returned); reserved in this call

<--> usbFlags

--> Specific direction of pipe ( kUSBIn or kUSBOut ) or kUSBAnyDirn as a wildcard <-- Direction of input or output pipe

<--> usbClassType

--> Specific endpoint type ( kUSBControl, kUSBInterrupt, or kUSBBulk ) or kUSBAnyType as a wildcard <-- Endpoint type

<-- usbWValue

Maximum packet size of endpoint

This function takes either an interface or pipe reference in the usbReference field. To find the first pipe, make a call to the function with an interface reference. To find the next pipe, enter the pipe reference returned by the previous call.

The usbFlags field takes either a specified endpoint direction or a wildcard of kUSBAnyDirn . The usbClassType field takes either a specified endpoint type or a wildcard of kUSBAnyType . For example, if you specify values for an input interrupt pipe, the function returns only the input interrupt pipes found. If a wildcard is used, all pipes of any type and direction found are returned.

Errors returned by the USBFindNextPipe function include

paramErr		usbBuffer pointer, usbReqCount, or usbActCount fields are not set to 0
kUSBUnknownDeviceErr	-6998	usbReference does not refer to a current device
kUSBUnknownPipeErr	-6997	pipe reference specified is unknown
kUSBNotFound	-6987	interface or configuration specified is not in configuration descriptor