midiStreamOpen
The midiStreamOpen function opens a MIDI stream for output. By default, the device is opened in paused mode. The stream handle retrieved by this function must be used in all subsequent references to the stream.
MMRESULT midiStreamOpen(
LPHMIDISTRM lphStream,
LPUINT puDeviceID,
DWORD cMidi,
DWORD_PTR dwCallback,
DWORD_PTR dwInstance,
DWORD fdwOpen
);
Parameters
lphStream
Pointer to a variable to contain the stream handle when the function returns.
puDeviceID
Pointer to a device identifier. The device is opened on behalf of the stream and closed again when the stream is closed.
cMidi
Reserved; must be 1.
dwCallback
Pointer to a callback function, an event handle, a thread identifier, or a handle of a window or thread called during MIDI playback to process messages related to the progress of the playback. If no callback mechanism is desired, specify NULL for this parameter.
dwInstance
Application-specific instance data that is returned to the application with every callback function.
fdwOpen
Callback flag for opening the device. One of the following callback flags must be specified.
| Value | Meaning |
| CALLBACK_EVENT | The dwCallback parameter is an event handle. This callback mechanism is for output only. |
| CALLBACK_FUNCTION | The dwCallback parameter is a callback procedure address. |
| CALLBACK_NULL | There is no callback mechanism. This is the default setting. |
| CALLBACK_THREAD | The dwCallback parameter is a thread identifier. |
| CALLBACK_WINDOW | The dwCallback parameter is a window handle. |
Return Values
Returns MMSYSERR_NOERROR if successful or an error otherwise. Possible error values include the following.
| Value | Description |
| MMSYSERR_BADDEVICEID | The specified device identifier is out of range. |
| MMSYSERR_INVALPARAM | The given handle or flags parameter is invalid. |
| MMSYSERR_NOMEM | The system is unable to allocate or lock memory. |
Requirements
** 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.
** Library:** Use Winmm.lib.
See Also