From ca621b3fbfaf3d11bb26971efe164a23793d22dd Mon Sep 17 00:00:00 2001 From: Paul Davis Date: Wed, 15 Jan 2014 15:00:07 -0500 Subject: [PATCH] improve comment explaining the use of alloca() --- libs/ardour/vst_plugin.cc | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/libs/ardour/vst_plugin.cc b/libs/ardour/vst_plugin.cc index 09a6f59e7c..5c9c94bdac 100644 --- a/libs/ardour/vst_plugin.cc +++ b/libs/ardour/vst_plugin.cc @@ -535,8 +535,14 @@ VSTPlugin::connect_and_run (BufferSet& bufs, BufferSet& silent_bufs = _session.get_silent_buffers(bufs_count); BufferSet& scratch_bufs = _session.get_scratch_buffers(bufs_count); - // VC++ doesn't support this C99 extension. Use alloca instead of dynamic - // array (rather than std::vector which allocs on the heap) + /* VC++ doesn't support the C99 extension that allows + + typeName foo[variableDefiningSize]; + + Use alloca instead of dynamic array (rather than std::vector which + allocs on the heap) because this is realtime code. + */ + float** ins = (float**)alloca(_plugin->numInputs*sizeof(float*)); float** outs = (float**)alloca(_plugin->numInputs*sizeof(float*));