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Beep function

Generates simple tones on the speaker. The function is synchronous; it performs an alertable wait and does not return control to its caller until the sound finishes.

Syntax


BOOL WINAPI Beep(
  _In_  DWORD dwFreq,
  _In_  DWORD dwDuration
);

Parameters

dwFreq [in]

The frequency of the sound, in hertz. This parameter must be in the range 37 through 32,767 (0x25 through 0x7FFF).

dwDuration [in]

The duration of the sound, in milliseconds.

Return value

If the function succeeds, the return value is nonzero.

If the function fails, the return value is zero. To get extended error information, call GetLastError.

Remarks

A long time ago, all PC computers shared a common 8254 programable interval timer chip for the generation of primitive sounds. The Beep function was written specifically to emit a beep on that piece of hardware.

On these older systems, muting and volume controls have no effect on Beep; you would still hear the tone. To silence the tone, you used the following commands:

net stop beep

sc config beep start= disabled

Since then, sound cards have become standard equipment on almost all PC computers. As sound cards became more common, manufacturers began to remove the old timer chip from computers. The chips were also excluded from the design of server computers. The result is that Beep did not work on all computers without the chip. This was okay because most developers had moved on to calling the MessageBeep function that uses whatever is the default sound device instead of the 8254 chip.

Eventually because of the lack of hardware to communicate with, support for Beep was dropped in Windows Vista and Windows XP 64-Bit Edition.

In Windows 7, Beep was rewritten to pass the beep to the default sound device for the session. This is normally the sound card, except when run under Terminal Services, in which case the beep is rendered on the client.

Examples

The following example demonstrates the use of this function.


Beep( 750, 300 );


Requirements

Minimum supported client

Windows XP [desktop apps only]

Minimum supported server

Windows Server 2003 [desktop apps only]

Header

WinBase.h (include Windows.h)

Library

Kernel32.lib

DLL

Kernel32.dll

See also

Error Handling Functions
MessageBeep
Notifying the User

 

 

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