Two same connections on WIN

We experience that when we try to connect a device two times.

RtMidiIn * rtMidiIn1 = new RtMidiIn();
rtMidiIn1->openPort(0);

RtMidiIn * rtMidiIn2 = new RtMidiIn();
rtMidiIn2->openPort(0);

then we get hard crash.

It is hardcrashing on win platform on mac it works nicely. ( ubuntu I havent tried yet)

Any idea why it is crashing?

[drewish]

I don't believe you can open the same port twice

[DouglasHeriot]

This works sometimes on OS X, but other times throws an error in MidiClientCreate.

I think it’s something you just shouldn’t do.

Would work if I make two different dlls but the same code. We need to access the same device twice. One for editor and one for when we play game from the editor. The editor version controls audio mixer the other controls game itself?

[drewish]

I'm sure you could find or write something to serve as a splitter and forward messages from one input to two virtual output ports

Hmm.. yes I can find... but how do I know if a specific port has been already opened?

can I check some rtmidi handles ( universal )?

[drewish]

There's a PR that I haven't gotten to look at yet: #30 You should give it a try and see if it works for your needs. If you do, please leave some feed back on it.

Thanks... anyway I tried to make two different dlls with the same code so that I'm sure there are no problems with two processes calling the same function on different thread. BUT even with two different dlls the app simply hangs when opening same ports.

On osx it works without any issue :-) even from single bundle I can open more connections to the same port.

[radarsat1]

Are you proposing that RtMidi should succeed in this case (which clearly doesn't work, and what would that mean semantically, anyways, to have the same port open twice..) or are you suggesting that it should protect you from doing this to avoid crashes?

We are developing in Unity3D. One connection controls editor audio mixer second connection controls in game things. Anyway if I have two apps running with the same dll the later started app simply crashes. Even if I make two different dlls one of the games always crashes. Any idea how to prevent this? On osx no problem. two games both running nicely.

First I will try to change polling getMessage to callback function. Then I think of mutex and lock every dll function we call.

Here is perfectly working Unity3d Editor, and two compiled apps.
https://www.dropbox.com/s/lipe6um9hj4b2m2/osx.mp4?dl=0

On windows we are unable to achieve this.

Can anyone help with this code?

https://www.dropbox.com/s/u26m35wx5en5mdb/rtmidiplugin.cpp?dl=0

How we should write windows dll so that it does not crashes. ? Mutexes? When polling data or using callback?

We are unable to solve this. Two different apps loading the same dll ( the dll resides in each apps path ) so the dll is loaded into each process memory space BUT whenever we are connected in one app to port lets say 0 and we try do the same in the other app the other app simple crashes.

[garyscavone]

The RtMidi code has checks for errors when instantiating. If the underlying system does not report an error in this case (opening the same device twice), then there is nothing we can do about it.