midiOutUnprepareHeader() private method

private midiOutUnprepareHeader ( HMIDIOUT hmo, IntPtr lpMidiOutHdr, UInt32 cbMidiOutHdr ) : MMRESULT
hmo HMIDIOUT
lpMidiOutHdr System.IntPtr
cbMidiOutHdr System.UInt32
return MMRESULT
Win32API Class Documentation
Example #1
0
        /// <summary>
        /// Sends a System Exclusive (sysex) message to this MIDI output device.
        /// </summary>
        /// <param name="data">The message to send (as byte array)</param>
        /// <exception cref="DeviceException">The message cannot be sent.</exception>
        public void SendSysEx(Byte[] data)
        {
            lock (this)
            {
                //Win32API.MMRESULT result;
                IntPtr           ptr;
                UInt32           size   = (UInt32)Marshal.SizeOf <Win32API.MIDIHDR>();
                Win32API.MIDIHDR header = new Win32API.MIDIHDR
                {
                    lpData = System.Runtime.InteropServices.Marshal.AllocHGlobal(data.Length)
                };
                for (int i = 0; i < data.Length; i++)
                {
                    System.Runtime.InteropServices.Marshal.WriteByte(header.lpData, i, data[i]);
                }
                header.dwBufferLength  = data.Length;
                header.dwBytesRecorded = data.Length;
                header.dwFlags         = 0;

                try
                {
                    ptr = System.Runtime.InteropServices.Marshal.AllocHGlobal(Marshal.SizeOf <Win32API.MIDIHDR>());
                }
                catch (Exception)
                {
                    System.Runtime.InteropServices.Marshal.FreeHGlobal(header.lpData);
                    throw;
                }

                try
                {
                    System.Runtime.InteropServices.Marshal.StructureToPtr(header, ptr, false);
                }
                catch (Exception)
                {
                    System.Runtime.InteropServices.Marshal.FreeHGlobal(header.lpData);
                    System.Runtime.InteropServices.Marshal.FreeHGlobal(ptr);
                    throw;
                }

                //result = Win32API.midiOutPrepareHeader(handle, ptr, size);
                //if (result == 0) result = Win32API.midiOutLongMsg(handle, ptr, size);
                //if (result == 0) result = Win32API.midiOutUnprepareHeader(handle, ptr, size);
                CheckReturnCode(Win32API.midiOutPrepareHeader(handle, ptr, size));
                CheckReturnCode(Win32API.midiOutLongMsg(handle, ptr, size));
                CheckReturnCode(Win32API.midiOutUnprepareHeader(handle, ptr, size));

                System.Runtime.InteropServices.Marshal.FreeHGlobal(header.lpData);
                System.Runtime.InteropServices.Marshal.FreeHGlobal(ptr);
            }
        }