Hey Oli,
i wanted to ask, if i need anything else to do except specifying how many channels i want in PLUG_CHANNEL_IO.
if i do the following: PLUG_CHANNEL_IO “2-2.2” it works fine, however if i try “2-2.2.2” the plugin crashes (in Bitwig) 
im using the latest version of windows 10
thanks in advance, Felix
so “2-2.2.2” would mean
multi output bus effects plugins are not very common, is that what you want?
you have to be more specific when you say something crashes for it to be useful. What plugin format were you using? Where does it crash?
If it’s a VST3 plugin, does it crash the VST3 validator etc.
Yes I want a multi out effect VST 3 plugin with 3 stereo output busses 
I just duplicated the IPlugEffect example and set the output to 2.2.2 - And i doesn´t crash in the VST TestHost. If I load it in Bitwig it crashes however, but I can´t tell you exactly where because i have to load the plugin manually… i didn´t quite get how to set it up correctly…
Its weird, because if I load the Drumsynth Example Plugin which also has 4 outputs it works just fine, so i guess it´s sth. that´s specific for FX.
It´s the same in FL - Drumsynth loads just fine, but if i activate the second channel of the FX Plugin the plugin is disabled, because of an error.
If i activate the second output in FL it gives me a:
Exception thrown at 0x00007FFCB06EBCFB (MultiOutTest.vst3) in FL64.exe: 0xC0000005: Access violation reading location 0xFFFFFFFFFFFFFFFF.
So the Plugin itself is being loaded without a problem, but sth. in the multi out doesnt seem to work…
EDIT: What i mean with: “i didnt get how to set it up” is that i tried to change the select_host script to take Bitwig. But if VS tries to start Bitwig, i get this:
Exception thrown at 0x00000000026403B4 in Bitwig Studio.exe: 0xC0000005: Access violation reading location 0x0000000000000000.
Don’t really have time to look into this since it’s pretty obscure. If I were you i would build a VST3 using the vst3 sdk with the bus format you want, compare the reported buses to iPlug2 version in validator etc, and see if that crashes. Also, the debugger should be able to help you get more meaning full info about the crashes