SoundSentryProc

The SoundSentryProc function is a library-defined callback function that produces a customized visual signal when the SoundSentry accessibility feature is on and a Win32-based application (or an application running in a window) generates a sound through the computer's built-in speaker.

LRESULT CALLBACK SoundSentryProc(
  DWORD dwMillisec,  // duration of visual signal
  DWORD fdwEffect    // effect-type flag
);
 

Parameters

dwMillisec

Specifies the duration, in milliseconds, of the visual signal that is displayed when a Win32-based application (or an application running in a window) generates a sound.

fdwEffect

Specifies the type of visual signal to display. Currently, this value must always be SSWF_CUSTOM.

Return Values

If the visual signal was or will be displayed correctly, the return value is TRUE. If the signal is asynchronous and the status is not available when the function is called, it should return TRUE.

If an error prevented the signal from being displayed, the return value is FALSE. To get extended error information, call GetLastError.

Remarks

The library that contains the SoundSentryProc function must be a 32-bit DLL, and the DLL must export a function with the name SoundSentryProc.

The SoundSentryProc function is called only after an application or library calls the SystemParametersInfo function, specifying the SPI_SETSOUNDSENTRY value and the address of a SOUNDSENTRY structure whose iWindowsEffect member is set to SSWF_CUSTOM.

QuickInfo

  Windows NT: Requires version 3.1 or later.
  Windows: Requires Windows 95 or later.
  Windows CE: Unsupported.
  Import Library: User-defined.

See Also

Accessibility Overview, Accessibility Functions, SOUNDSENTRY, SystemParametersInfo