- 1 year ago
In which context is the MidiInProc callback executed?
The MidiInProc
callback in the Windows Multimedia API is executed in the context of the thread that created the MIDI input device.
When you open a MIDI input device using the midiInOpen
function and provide a callback function (MidiInProc), the operating system creates a separate thread dedicated to handling MIDI input events. This thread continuously monitors the MIDI input device for incoming MIDI messages.
When a MIDI message is received, the MidiInProc
callback function is invoked by the operating system in the context of that dedicated thread. The callback function is passed the MIDI input device handle, the MIDI message, and any user-defined callback data.
It's important to note that the MidiInProc
callback function should be implemented in a way that is efficient and doesn't block or perform lengthy operations, as it is executed in the context of the dedicated MIDI input thread. Any processing in the callback function should be kept minimal to ensure the timely handling of incoming MIDI messages.
Additionally, it's recommended to avoid making any calls to other Windows API functions that may interact with the UI or perform blocking operations, as it can impact the responsiveness of the MIDI input thread and potentially introduce latency in the MIDI input processing.
By understanding the context in which the MidiInProc
callback is executed, you can design your MIDI input handling code appropriately to ensure smooth and responsive MIDI input processing.