[Jackaudio] Jack C++ midi structural considerations

[Christopher Arndt]

Am 11.06.20 um 11:59 schrieb Kjetil Matheussen:
> On Thu, Jun 11, 2020 at 11:55 AM Kjetil Matheussen <k.s.matheussen at gmail.com> wrote:
>>
>> On Thu, May 14, 2020 at 6:37 PM Christopher Arndt <chris at chrisarndt.de> wrote:
>>> http://www.music.mcgill.ca/~gary/rtmidi/index.html
>>>
>>
>> Last time I checked (2012), rtmidi allocated memory here and there
>> from the system in the realtime thread when sending and receiving MIDI
>> messages.
> 
> Yes, it's still using std::vector to store messages in:
> https://github.com/thestk/rtmidi/blob/master/RtMidi.cpp#L640

If I interpret the code correctly, you could prevent allocations, if you
call

	data->rtMidiIn->message.reserve(4)

in 'MidiInJack::initialize'
(https://github.com/thestk/rtmidi/blob/master/RtMidi.cpp#L3088) and
ignore SysEx messages. The usual (or at least a common) way to use
RtMidi is to copy it into your project anway, so you can make any
changes you like to it.

BTW, I would never use 'getMessage', but attach a callback via
'RtMidiIn::setCallback'.

If you need to handle SysEx messages, you could set the maximum capacity
with 'reserve' to the size of the biggest SysEx message you expect to
handle.


Chris