The MM_WOM_OPEN message is sent to a window when the given waveform-audio output device is opened.
MM_WOM_OPEN wParam = (WPARAM) hOutputDev lParam = reserved
Handle to the device that was opened.
Reserved; must be zero.
This message does not return a value.
** Windows NT/2000/XP:** Included in Windows NT 3.1 and later.
** Windows 95/98/Me:** Included in Windows 95 and later.
** Header:** Declared in Mmsystem.h; include Windows.h.