The Be Book - Classes And Methods - The Midi Kit
| Class Overview |
BMidiPort(const char* name = NULL);Creates a new BMidiPort object
and opens it on the named port. If no name
is given, the object remains unopened until
Open()
is called.
bool AllNotesOff(bool controlMsgOnly,
uint32 time = B_NOW);Commands the BMidiPort object to issue
an All Notes Off MIDI message to the MIDI-Out port. If
controlOnly is true,
only the All Notes Off message is sent. If it's
false, a Note Off message is also sent for every
key number on every channel.
void Close();Closes the object's MIDI port. The port should have been previously
opened through a call to
Open().
int32 CountDevices();status_t GetDeviceName(int32 n,
char* name,
size_t bufSize = B_OS_NAME_LENGTH);These two function work together to let you retrieve the names of
all MIDI ports. CountDevices() returns the
number of MIDI ports that are supported by the machine.
GetDeviceName() returns, in
name, the name of the
n'th MIDI port.
bufSize is the length of the
name buffer, in bytes. It needn't be longer than
B_OS_NAME_LENGTH (defined in
OS.h).
GetDeviceName() returns…
| Return Code | Description |
|---|---|
| Success. |
|
|
| The device name length is greater than
|
status_t InitCheck() const;Returns the status of the previous port-opening call. This function is provided primarily so you can get the status after opening the port through the constructor.
| Return Code | Description |
|---|---|
| The port was successfully opened. |
POSIX errors | The open was thwarted. |
status_t Open(const char* name);Opens the MIDI port identified by name, so the object can read and write
MIDI data. Use the
GetDeviceName()
function to get the names of the MIDI
ports. The object isn't given exclusive access to the ports that it has
opened—other BMidiPort objects, potentially from other
applications, can open the same MIDI ports. When you're finished with the
ports, you should close them through a (single) call to
Close().
The MIDI-Out connection is active from the moment the object is opened:
Messages that arrive through the MIDI hook functions are automatically
sent to the MIDI-Out port. To begin reading from the MIDI-In port, you
have to invoke the object's
Start()
function.
The function returns B_OK if the port was
successfully opened.
virtual status_t Start();virtual void Stop();Start() tells the object to begin
listening to MIDI-In. For each MIDI message that it hears, the object calls
the appropriate spray function.
Stop() tells the object to stop
listening to MIDI-In.
Neither of these functions affects the MIDI-Out side of the port.
The BMidiPort class implements the MIDI
hook functions to send MIDI data to the MIDI-Out side of the port. For the
syntax of the MIDI hook functions, see the
BMidi
class.
