Error when calling MIDIObjectGetStringProperty from RubyMotion

app_delegate.rb

class AppDelegate
  def application(application, didFinishLaunchingWithOptions:launchOptions)
    # MIDIClientRef client = NULL;
    client = Pointer.new(MIDIClientRef.type)

    # MIDIClientCreate(CFSTR("Core MIDI to System Sounds Demo"), MyMIDINotifyProc, self, &client);
    MIDIClientCreate("Core MIDI to System Sounds Demo", method(:myMIDINotifyProc), nil, client)
  
    # MIDIPortRef inPort = NULL;
    inPort = Pointer.new(MIDIPortRef.type)

    # MIDIInputPortCreate(client, CFSTR("Input port"), MyMIDIReadProc, self, &inPort);
    MIDIInputPortCreate(client[0], "Input port", method(:myMIDIReadProc), nil, inPort)
    
    # MIDINetworkSession* session = [MIDINetworkSession defaultSession];
    session = MIDINetworkSession.defaultSession
    # session.enabled = YES;
    session.enabled = true
    # session.connectionPolicy = MIDINetworkConnectionPolicy_Anyone;
    session.connectionPolicy = MIDINetworkConnectionPolicy_Anyone
	
    # unsigned long sourceCount = MIDIGetNumberOfSources();
    sourceCount = MIDIGetNumberOfSources()

    # NSLog([NSString stringWithFormat:@"%ld sources\n", sourceCount]);
    puts "#{sourceCount} sources"

    # for (int i = 0; i < sourceCount; ++i) {
    sourceCount.times do |i|
      # MIDIEndpointRef src = MIDIGetSource(i);
      src = MIDIGetSource(i)

      # CFStringRef endpointName = NULL;
      endpointName = Pointer.new(:string)

      # OSStatus nameErr = MIDIObjectGetStringProperty(src, kMIDIPropertyName, &endpointName);
      nameErr = MIDIObjectGetStringProperty(src, KMIDIPropertyName, endpointName);

      # if (noErr == nameErr) {
      if (nameErr == 0)
        # NSLog([NSString stringWithFormat:@"  source %d: %@\n", i, endpointName]);
        puts "  source #{i}: #{endpointName[0]}"
      # }
      end

      # MIDIPortConnectSource(inPort, src, NULL);
      MIDIPortConnectSource(inPort[0], src, nil);

    # }
    end

    true
  end

  # static void	MyMIDIReadProc(const MIDIPacketList *pktlist, void *refCon, void *connRefCon)
  def myMIDIReadProc(pktlist, refCon, connRefCon)
  # {

    # MIDIPacket *packet = (MIDIPacket *)pktlist->packet;
    packet = pktlist.packet

    # Byte midiCommand = packet->data[0] >> 4;
    midiCommand = packet.data[0] >> 4

    # // is it a note-on
    # if (midiCommand == 0x09) {
    if (midiCommand == 0x09)

      # Byte note = packet->data[1] & 0x7F;
      note = packet.data[1] & 0x7F

      # Byte veolocity = packet->data[2] & 0x7F;
      veolocity = packet.data[2] & 0x7F

      # NSLog([NSString stringWithFormat:
      #       @"Note ON. Note=%d, Velocity=%d", note, veolocity]);
      puts "Note ON. Note=#{note}, Velocity=#{veolocity}"
    # }
    end

  # }
  end

  # void MyMIDINotifyProc (const MIDINotification  *message, void *refCon) {
  def myMIDINotifyProc (message, refCon)
    # NSLog([NSString stringWithFormat:
    #          @"MIDI Notify, messageId=%d,", message->messageID]);
    puts "MIDI Notify, messageId=#{message.messageID},"
  # }
  end
  
end

rake_simulator.txt

** Invoke default (first_time)
** Invoke simulator (first_time)
** Invoke build:simulator (first_time)
** Execute build:simulator
/usr/bin/env VM_KERNEL_PATH="/Library/RubyMotion/data/6.0/iPhoneSimulator/kernel-i386.bc" VM_OPT_LEVEL="0" /Library/RubyMotion/bin/ruby --uses-bs "/Library/RubyMotion/data/6.0/BridgeSupport/RubyMotion.bridgesupport"  --uses-bs "/Library/RubyMotion/data/6.0/BridgeSupport/UIKit.bridgesupport"  --uses-bs "/Library/RubyMotion/data/6.0/BridgeSupport/CoreVideo.bridgesupport"  --uses-bs "/Library/RubyMotion/data/6.0/BridgeSupport/CoreImage.bridgesupport"  --uses-bs "/Library/RubyMotion/data/6.0/BridgeSupport/Security.bridgesupport"  --uses-bs "/Library/RubyMotion/data/6.0/BridgeSupport/Foundation.bridgesupport"  --uses-bs "/Library/RubyMotion/data/6.0/BridgeSupport/CoreGraphics.bridgesupport"  --uses-bs "/Library/RubyMotion/data/6.0/BridgeSupport/CoreFoundation.bridgesupport"  --uses-bs "/Library/RubyMotion/data/6.0/BridgeSupport/ImageIO.bridgesupport"  --uses-bs "/Library/RubyMotion/data/6.0/BridgeSupport/QuartzCore.bridgesupport"  --uses-bs "/Library/RubyMotion/data/6.0/BridgeSupport/CoreText.bridgesupport"  --uses-bs "/Library/RubyMotion/data/6.0/BridgeSupport/MobileCoreServices.bridgesupport"  --uses-bs "/Library/RubyMotion/data/6.0/BridgeSupport/CFNetwork.bridgesupport"  --uses-bs "/Library/RubyMotion/data/6.0/BridgeSupport/Accelerate.bridgesupport"  --uses-bs "/Library/RubyMotion/data/6.0/BridgeSupport/SystemConfiguration.bridgesupport"  --uses-bs "/Library/RubyMotion/data/6.0/BridgeSupport/CoreMIDI.bridgesupport"  --emit-llvm "./build/iPhoneSimulator-6.0-Development/objs/usr/local/src/core-midi-test/app/app_delegate.rb.i386.bc" MREP_0ED0A7DDC0694BB68B622E2C931892FA "/usr/local/src/core-midi-test/app/app_delegate.rb"
/Library/RubyMotion/bin/llc "./build/iPhoneSimulator-6.0-Development/objs/usr/local/src/core-midi-test/app/app_delegate.rb.i386.bc" -o="./build/iPhoneSimulator-6.0-Development/objs/usr/local/src/core-midi-test/app/app_delegate.rb.i386.s" -march=x86 -relocation-model=pic -disable-fp-elim -jit-enable-eh -disable-cfi
/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin/gcc -fexceptions -c -arch i386 "./build/iPhoneSimulator-6.0-Development/objs/usr/local/src/core-midi-test/app/app_delegate.rb.i386.s" -o "./build/iPhoneSimulator-6.0-Development/objs/usr/local/src/core-midi-test/app/app_delegate.rb.i386.o"
/usr/bin/lipo -create "./build/iPhoneSimulator-6.0-Development/objs/usr/local/src/core-midi-test/app/app_delegate.rb.i386.o" -output "./build/iPhoneSimulator-6.0-Development/objs/usr/local/src/core-midi-test/app/app_delegate.rb.o"
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang++ "./build/iPhoneSimulator-6.0-Development/objs/init.mm" -arch i386 -isysroot "/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator6.0.sdk" -miphoneos-version-min=6.0 -F/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator6.0.sdk/System/Library/Frameworks -fexceptions -fblocks -fobjc-legacy-dispatch -fobjc-abi-version=2 -c -o "./build/iPhoneSimulator-6.0-Development/objs/init.o"
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang++ "./build/iPhoneSimulator-6.0-Development/objs/main.mm" -arch i386 -isysroot "/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator6.0.sdk" -miphoneos-version-min=6.0 -F/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator6.0.sdk/System/Library/Frameworks -fexceptions -fblocks -fobjc-legacy-dispatch -fobjc-abi-version=2 -c -o "./build/iPhoneSimulator-6.0-Development/objs/main.o"
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang++ -o "./build/iPhoneSimulator-6.0-Development/core-midi-test.app/core-midi-test" "./build/iPhoneSimulator-6.0-Development/objs/init.o" "./build/iPhoneSimulator-6.0-Development/objs/main.o" "/Library/RubyMotion/data/6.0/iPhoneSimulator/UIKit_stubs.o" "/Library/RubyMotion/data/6.0/iPhoneSimulator/Foundation_stubs.o" "/Library/RubyMotion/data/6.0/iPhoneSimulator/CoreGraphics_stubs.o" "/Library/RubyMotion/data/6.0/iPhoneSimulator/CoreFoundation_stubs.o" "/Library/RubyMotion/data/6.0/iPhoneSimulator/CFNetwork_stubs.o" "./build/iPhoneSimulator-6.0-Development/objs/usr/local/src/core-midi-test/app/app_delegate.rb.o" -arch i386 -isysroot "/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator6.0.sdk" -miphoneos-version-min=6.0 -F/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator6.0.sdk/System/Library/Frameworks -L/Library/RubyMotion/data/6.0/iPhoneSimulator -lmacruby-static -lobjc -licucore  -framework UIKit -framework CoreVideo -framework CoreImage -framework Security -framework Foundation -framework CoreGraphics -framework CoreFoundation -framework ImageIO -framework QuartzCore -framework CoreText -framework MobileCoreServices -framework CFNetwork -framework Accelerate -framework SystemConfiguration -framework CoreMIDI   
/usr/bin/plutil -convert binary1 "./build/iPhoneSimulator-6.0-Development/core-midi-test.app/Info.plist"
/usr/bin/dsymutil "./build/iPhoneSimulator-6.0-Development/core-midi-test.app/core-midi-test" -o "./build/iPhoneSimulator-6.0-Development/core-midi-test.dSYM"
** Execute simulator
DYLD_FRAMEWORK_PATH="/Applications/Xcode.app/Contents/Developer/../Frameworks":"/Applications/Xcode.app/Contents/Developer/../OtherFrameworks" /Library/RubyMotion/bin/sim 2 1 6.0 "/Applications/Xcode.app/Contents/Developer" "./build/iPhoneSimulator-6.0-Development/core-midi-test.app"
(main)> 1 sources
2013-01-07 17:28:14.082 core-midi-test[20445:c07] app_delegate.r:in `block in application:didFinishLaunchingWithOptions:': expected instance of Pointer, got `#<MIDIEndpointRef:0x9564630>' (MIDIEndpointRef) (TypeError)
  from app_delegate.rb:29:in `application:didFinishLaunchingWithOptions:'
2013-01-07 17:28:14.084 core-midi-test[20445:c07] *** Terminating app due to uncaught exception 'TypeError', reason: 'app_delegate.r:in `block in application:didFinishLaunchingWithOptions:': expected instance of Pointer, got `#<MIDIEndpointRef:0x9564630>' (MIDIEndpointRef) (TypeError)
	from app_delegate.rb:29:in `application:didFinishLaunchingWithOptions:'
'
*** First throw call stack:
(0x1807012 0x17be7e 0xd8314 0x2a22 0x27d5)
libc++abi.dylib: terminate called throwing an exception
*** simulator session ended with error: Error Domain=DTiPhoneSimulatorErrorDomain Code=1 "The simulated application quit." UserInfo=0x100121440 {NSLocalizedDescription=The simulated application quit., DTiPhoneSimulatorUnderlyingErrorCodeKey=-1}
rake aborted!
Command failed with status (1): [DYLD_FRAMEWORK_PATH="/Applications/Xcode.a...]
/Users/jedidiah/.rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.3/lib/rake/file_utils.rb:53:in `block in create_shell_runner'
/Users/jedidiah/.rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.3/lib/rake/file_utils.rb:45:in `call'
/Users/jedidiah/.rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.3/lib/rake/file_utils.rb:45:in `sh'
/Users/jedidiah/.rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.3/lib/rake/file_utils_ext.rb:40:in `sh'
/Library/RubyMotion/lib/motion/project.rb:101:in `block in <top (required)>'
/Users/jedidiah/.rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.3/lib/rake/task.rb:228:in `call'
/Users/jedidiah/.rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.3/lib/rake/task.rb:228:in `block in execute'
/Users/jedidiah/.rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.3/lib/rake/task.rb:223:in `each'
/Users/jedidiah/.rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.3/lib/rake/task.rb:223:in `execute'
/Users/jedidiah/.rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.3/lib/rake/task.rb:166:in `block in invoke_with_call_chain'
/Users/jedidiah/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/monitor.rb:211:in `mon_synchronize'
/Users/jedidiah/.rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.3/lib/rake/task.rb:159:in `invoke_with_call_chain'
/Users/jedidiah/.rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.3/lib/rake/task.rb:187:in `block in invoke_prerequisites'
/Users/jedidiah/.rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.3/lib/rake/task.rb:185:in `each'
/Users/jedidiah/.rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.3/lib/rake/task.rb:185:in `invoke_prerequisites'
/Users/jedidiah/.rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.3/lib/rake/task.rb:165:in `block in invoke_with_call_chain'
/Users/jedidiah/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/monitor.rb:211:in `mon_synchronize'
/Users/jedidiah/.rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.3/lib/rake/task.rb:159:in `invoke_with_call_chain'
/Users/jedidiah/.rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.3/lib/rake/task.rb:152:in `invoke'
/Users/jedidiah/.rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.3/lib/rake/application.rb:143:in `invoke_task'
/Users/jedidiah/.rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.3/lib/rake/application.rb:101:in `block (2 levels) in top_level'
/Users/jedidiah/.rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.3/lib/rake/application.rb:101:in `each'
/Users/jedidiah/.rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.3/lib/rake/application.rb:101:in `block in top_level'
/Users/jedidiah/.rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.3/lib/rake/application.rb:110:in `run_with_threads'
/Users/jedidiah/.rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.3/lib/rake/application.rb:95:in `top_level'
/Users/jedidiah/.rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.3/lib/rake/application.rb:73:in `block in run'
/Users/jedidiah/.rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.3/lib/rake/application.rb:160:in `standard_exception_handling'
/Users/jedidiah/.rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.3/lib/rake/application.rb:70:in `run'
/Users/jedidiah/.rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.3/bin/rake:33:in `<top (required)>'
/Users/jedidiah/.rvm/gems/ruby-1.9.3-p194/bin/rake:19:in `load'
/Users/jedidiah/.rvm/gems/ruby-1.9.3-p194/bin/rake:19:in `<main>'
/Users/jedidiah/.rvm/gems/ruby-1.9.3-p194/bin/ruby_noexec_wrapper:14:in `eval'
/Users/jedidiah/.rvm/gems/ruby-1.9.3-p194/bin/ruby_noexec_wrapper:14:in `<main>'
Tasks: TOP => default => simulator

Rakefile

# -*- coding: utf-8 -*-
$:.unshift("/Library/RubyMotion/lib")
require 'motion/project'

Motion::Project::App.setup do |app|
  # Use `rake config' to see complete project settings.
  app.name = 'core-midi-test'
  app.frameworks << 'CoreMIDI'
end