Beep function (utilapiset.h)
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.
BOOL Beep( [in] DWORD dwFreq, [in] DWORD dwDuration );
The frequency of the sound, in hertz. This parameter must be in the range 37 through 32,767 (0x25 through 0x7FFF).
The duration of the sound, in milliseconds.
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.
A long time ago, all PC computers shared a common 8254 programmable 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.
The following example demonstrates the use of this function.
Beep( 750, 300 );
|Minimum supported client||Windows XP [desktop apps | UWP apps]|
|Minimum supported server||Windows Server 2003 [desktop apps | UWP apps]|
|Header||utilapiset.h (include Windows.h)|