freq (ULONG) - input

Cycles per second (Hertz) in the range of 0x25 to 0x7FFF.

dur (ULONG) - input

The length of the sound in milliseconds.

ulrc (APIRET) - returns

Return Code.

DosBeep returns one of the following values:

• NO_ERROR 395
  ERROR_INVALID_FREQUENCY
  For a full list of error codes, see Errors.