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PVST crash in my test VST

Posted: Sun Oct 02, 2022 2:30 pm
by UNZ
i have a very simple vst (2.4) with one parameter. it mostly works, but:

if i change the parameter value from the buzz parameter gui or from pxp, PVST crashes with a null reference exception.
changing the parameter value in pvst's built-in parameter gui works.

unfortunately i don't get a proper stack trace when it crashes so i have no idea what is null.
what could be the problem?
the plugin only relies on the C API btw, so no AudioEffect/AudioEffectX classes, but that should not matter.

attached: the test vst.

edit: tried it on another machine with b34, it worked, then updated to b40: crashes.

EDIT: looks like i found the issue: it happens when numPrograms is set to 0, is a VST supposed to always have at least 1 or is this a bug?

Re: PVST crash in my test VST

Posted: Mon Oct 03, 2022 12:09 pm
by UNZ
so after a bit of thinking about this and testing some hosts here are my thoughts:
some hosts don't seem to care for NumPrograms = 0 and work just fine, others have issues with it.
i could not find a definitive answer in the VST standard that says anything about 0 being legal or not.

i think even if the standard says it's illegal, i think it would be prudent of PVST to guard against this.