getPortList returns an empty set if the requirements cannot be met.

It's up to the developers to deal with this case, anyway.

Author: Tobias Schlemmer

RtMidi.cpp

@@ -4338,7 +4338,7 @@ namespace rtmidi{
 	PortList MidiInWinMM :: getPortList(int capabilities)
 	{
 		WinMidiData *data = static_cast<WinMidiData *> (apiData_);
-		if (!data) return PortList();
+		if (!data || capabilities != PortDescriptor::INPUT) return PortList();
 		return WinMMPortDescriptor::getPortList(PortDescriptor::INPUT,data->getClientName());
 	}
 
@@ -4587,7 +4587,7 @@ namespace rtmidi{
 	PortList MidiOutWinMM :: getPortList(int capabilities)
 	{
 		WinMidiData *data = static_cast<WinMidiData *> (apiData_);
-		if (!data) return PortList();
+		if (!data || capabilities != PortDescriptor::OUTPUT) return PortList();
 		return WinMMPortDescriptor::getPortList(PortDescriptor::OUTPUT,data->getClientName());
 	}