This example generates a beep for one second at a frequency of 1440 Hz.

#define INCL_DOSPROCESS    /* DOS Process and thread values */
#define INCL_DOSERRORS     /* DOS Error values */
#include <os2.h>
#include <stdio.h>

int main(VOID) {

   APIRET   rc = NO_ERROR;     /* Return code                       */

   rc = DosBeep(1440L,         /* Beep frequency, in hertz          */
                1000L);        /* Duration of beep, in milliseconds */

   if (rc != NO_ERROR) {
      printf("DosBeep error: return code = %u\n", rc);
      return 1;
   }

   return NO_ERROR;
}