IStiDevice::RawReadCommand method (sti.h)

The IStiDevice::RawReadCommand method reads command information from a still image device.

Syntax

HRESULT RawReadCommand(
  [in, out]      LPVOID       lpBuffer,
  [in, out]      LPDWORD      lpdwNumberOfBytes,
  [in, optional] LPOVERLAPPED lpOverlapped
);

Parameters

[in, out] lpBuffer

Caller-supplied pointer to a buffer to receive data read from the device.

[in, out] lpdwNumberOfBytes

Caller-supplied pointer to a DWORD. The caller must load the DWORD with the number of bytes in the buffer pointed to by lpBuffer. On return, it will contain the number of bytes actually read.

[in, optional] lpOverlapped

Optional, caller-supplied pointer to an OVERLAPPED structure (described in the Microsoft Windows SDK documentation).

Return value

If the operation succeeds, the method returns S_OK. Otherwise, it returns one of the STIERR-prefixed error codes defined in stierr.h.

Remarks

The IStiDevice::RawReadCommand method calls IStiUSD::RawReadCommand, which is exported by vendor-supplied minidrivers. The meaning of buffer contents are vendor-defined.

It is only necessary to call IStiDevice::RawReadCommand if command and data information are read from a device by different methods. For other devices, IStiDevice::RawReadData can be used for both commands and data.

Before calling IStiDevice::RawReadCommand, clients of the IStiDevice COM interface must call IStillImage::CreateDevice to obtain an IStiDevice interface pointer, which provides access to a specified device.

A call to IStiDevice::RawReadCommand must be preceded by a call to IStiDevice::LockDevice and followed by a call to IStiDevice::UnLockDevice.

Requirements