Expand Minimize

WinUsb_WriteIsochPipe routine

The WinUsb_WriteIsochPipe function writes the contents of a caller-supplied buffer to an isochronous OUT endpoint, starting on a specified frame number.

Syntax


BOOL __stdcall WinUsb_WriteIsochPipe(
  _In_      PWINUSB_ISOCH_BUFFER_HANDLE BufferHandle,
  _In_      ULONG Offset,
  _In_      ULONG Length,
  _Inout_   PULONG FrameNumber,
  _In_opt_  LPOVERLAPPED Overlapped
);

Parameters

BufferHandle [in]

An opaque handle to the transfer buffer that was registered by a previous call to WinUsb_RegisterIsochBuffer.

Offset [in]

Offset into the buffer relative to the start the transfer.

Length [in]

Length in bytes of the transfer buffer.

FrameNumber [in, out]

On input, indicates the starting frame number for the transfer. On output, contains the frame number of the frame that follows the last frame used in the transfer.

Overlapped [in, optional]

Pointer to an OVERLAPPED structure used for asynchronous operations.

Return value

WinUsb_WriteIsochPipe returns TRUE if the operation succeeds. Otherwise this function returns FALSE, and the caller can retrieve the logged error by calling GetLastError.

Remarks

WinUsb_WriteIsochPipe packetizes the transfer buffer so that in each interval, the host can send the maximum bytes allowed per interval. The maximum bytes is as specified by the endpoint descriptor for full and high-speed endpoints, and endpoint companion descriptor for SuperSpeed endpoints. If the caller submits multiple write requests to stream data to the device, the transfer size should be a multiple of the maximum bytes per interval (as returned by WinUsb_QueryPipeEx) * 8 / interval.

Requirements

Minimum supported client

Windows 8.1

Minimum supported server

Windows Server 2012 R2

Header

Winusb.h (include Winusb.h)

Library

Winusb.lib

See also

WinUSB Functions
Send USB isochronous transfers from a WinUSB desktop app

 

 

Send comments about this topic to Microsoft

Show:
© 2014 Microsoft