CeRapiInvoke (RAPI) (Windows Embedded CE 6.0)

1/6/2010

This function can be used as a general-purpose mechanism to remotely execute a routine on a remote Windows Embedded CE-based device.

Syntax

HRESULT CeRapiInvoke(
  LPCWSTR pDllPath,
  LPCWSTR pFunctionName,
  DWORD cbInput,
  BYTE* pInput,
  DWORD* pcbOutput,
  BYTE** ppOutput,
  IRAPIStream** ppIRAPIStream,
  DWORD dwReserved
);

Parameters

• pDllPath
  [in] Pointer to a string buffer containing the name of a DLL that is on the Windows Embedded CE-based device and that contains the function identified in pFunctionName.

• pFunctionName
  [in] Pointer to a string buffer containing the name of the function that RAPI should call on the Windows Embedded CE-based device.

• cbInput
  [in] Number of bytes in the input buffer *pInput.

• pInput
  [in] Pointer to a buffer containing the input data.

• pcbOutput
  [out] Pointer to a variable that is set to the number of bytes in the output buffer ppOutput when the function returns.

• ppOutput
  [out] Pointer to a variable that is set to the location of the output buffer upon return.

• ppIRAPIStream
  [in, out] The ppIRAPIStream parameter specifies block mode or stream mode. Select block mode by supplying the value NULL. Select stream mode by supplying a valid pointer to a variable of type IRAPIStream; this IRAPIStream interface can be used for a direct transfer of data. If ppIRAPIStream is not NULL, the pFunctionName parameter on the Windows Embedded CE-based device will be passed a pointer to the IRAPIStream interface.

• dwReserved
  Reserved.

Return Value

If RAPI services on the Windows Embedded CE-based device successfully locate and call the client function, then in Block Mode the return value is that which is returned on the Windows Embedded CE-based device by the called function. In Stream Mode, the return value is S_OK. If the function was not called successfully, or an exception occurred during its execution, an error code is returned.

The CeGetLastError function can be used to get the error code, which takes the value set by pFunctionName, including the following values:

• HRESULT_FROM_WIN32(ERROR_MOD_NOT_FOUND)
  The LoadLibrarypDllPath call failed on the device.

• HRESULT_FROM_WIN32(ERROR_INVALID_PARAMETER)
  The GetProcAddress of pFunctionName call on the device failed.

• HRESULT_FROM_WIN32(ERROR_EXCEPTION_IN_SERVICE)
  An exception occurred during execution of pFunctionName.

Remarks

CeRapiInvoke loads the device-side DLL named in pDllPath, then calls the RAPI extension named in pFunctionName. It is the responsibility of the RAPI extension to release the IRAPIStream object (that is, to call pIRAPIStream->Release();).

An application should allocate memory for the pInput parameter with the LocalAlloc function. The caller is responsible for freeing pInput. The system allocates memory for the ppOutput parameter. When the application is completed with the buffer, it should free the memory with the LocalFree function.

The CeRapiInvoke function operates in either block mode or stream mode. In block mode, the caller passes the data in a single buffer as an input parameter and receives the response in a single buffer as an output parameter. This is a synchronous call, thus all input or output data must be present in memory at the time of the call. In stream mode, the CeRapiInvoke function returns a pointer to an IStream type interface that can be used to exchange arbitrary sized data in any order and direction. In this mode, the caller can still pass data in a single buffer as an input parameter, but from that point on all data should be exchanged by means of the stream. Thus the data can be read, written, and stored in chunks. Streaming is significantly faster than block mode.

The ppIRAPIStream parameter specifies block mode or stream mode. Select block mode by supplying the value NULL. Select stream mode by supplying a valid pointer to a variable of type IRAPIStream; this IRAPIStream interface can be used for a direct transfer of data. If ppIRAPIStream is not NULL, the pFunctionName parameter on the Windows Embedded CE device will be passed a pointer to the IRAPIStream interface.

The IRAPIStreamdefinition is based on IStream and has been expanded by two new methods to allow the setting of timeouts. These methods, IRAPIStream::SetRapiStat and IRAPIStream::GetRapiStat, are modeledafter the IStream::Stat method.

The IRAPIStream object does not guarantee the reception of data by the device. It is up to your application to implement application-level ACK. The device application should send an acknowledgement code after it has succeeded in reading all of the data from the stream. After the desktop application has written to the stream, it should wait until it receives the acknowledgement code from the device application before it releases the stream.

Requirements

See Also

Reference

RAPI Functions

Other Resources

CAB Wizard