I'm pretty sure that the new Borland compiler has a
Sound(Frequency, Duration) function. The old one should have one too. Do you have a sound.h file? In true-DOS this would probably only work through the internal speaker
Microsoft has a Beep(Frequency, Duration) function. But, it does different things depending on your hardware and operating system. As I recall, it only works "as-expected" with WinNT or WinXP and only if you don't have a sound card/external speakers... Weird!
Those WINAPI sound functions that you found look like MIDI functions, which should work... if you can find the documentation... And if they are from the Turbo C++ compiler. If it's really a DOS compiler, it shouldn't have a windows.h file!
