subtype subString is String(1..64);
 
   package String_Address_Conversion is new System.Address_To_Access_Conversions(substring);
   use String_Address_Conversion;
 
   procedure Play is
 
      Error : PmError;
 
      PortMidiStream_Ptr,
      OutputDriverInfo_Ptr,
      Time_Info_Ptr  : System.Address;
 
      Current_DeviceInfo : DeviceInfo;
 
      Device : Natural;
 
 
   begin
 
      Error := Pm_Initialize;
      New_Line;
      for I in 0..Pm_CountDevices loop
         Current_DeviceInfo := DeviceInfo_Conversion.To_Pointer(Pm_GetDeviceInfo(I)).all;
         Put(I);
         Put_Line(" : " & To_Pointer(Current_DeviceInfo.Name).all);
      end loop;
      New_Line;
      Put("Choose device : " );
      Get(Device);