WriteString

Sends data to a device.

Syntax

virtual HRESULT WriteString(const CString& strData, bool bFlush = true, long lTimeout = CUR_TIMEOUT) override;

virtual HRESULT WriteString(BSTR strData, bool bFlush = true, long lTimeout = CUR_TIMEOUT) override;

virtual HRESULT WriteString(LPCTSTR strData, bool bFlush = true, long lTimeout = CUR_TIMEOUT) override;

Parameters

strData

[in] String data to send to the device.

bFlush

[in] If true, the formatted I/O write buffer is flushed to the device.

lTimeout

[in] I/O timeout value in milliseconds.

Return value

Returns S_OK if successful, otherwise a failure HRESULT.

Remarks

The WriteString function sends string data to the formatted I/O write buffer. If the bFlush parameter is true, then the contents of the I/O write buffer are flushed to the device. If bFlush is false, then the data is queued in the write buffer until the buffer is full or a subsequent operation forces a flush. Queueing data in this fashion can improve I/O performance by reducing the number of I/O roundtrips to the device.

Example

The following example demonstrates use of the WriteString function.

STDMETHODIMP Acme4321::IAcme4321_Configure(BSTR bstrSource1, BSTR bstrSource2, BSTR bstrSource3)
{
  HRESULT hr = S_OK;

  // Queue up commands in the write buffer
  hr = io.WriteStringNoPoll(bstrSource1, false);
  hr = io.WriteStringNoPoll(bstrSource2, false);

  // Send string and flush buffer to device
  hr = io.WriteString(bstrSource3);

  return hr;
}