public struct WAVEHDR

  public WaveHdrFlags dwFlags; // assorted flags (see defines)

  public IntPtr lpNext; // PWaveHdr, reserved for driver

Structure WAVEHDR

  Dim dwFlags As WaveHdrFlags

WaveHdrFlags

public static extern uint waveInAddBuffer(IntPtr hwi, ref WAVEHDR pwh, uint cbwh);

Shared Function waveInAddBuffer(<MarshalAs(UnmanagedType.I4)> ByVal hwi As Integer, ByRef pwh As WAVEHDR, ByVal cbwh As UInteger) As MMRESULT

WAVEHDR

When recording waveform audio, usually buffers are allocated with unmanaged functions and kept in an IntPtr() array; for this reason the function is provided in two versions, one processing a WAVEHDR ByRef and the other working with an IntPtr.

Instead of allocating memory using an unmanaged function, it is possible to lock the WAVEHDR and Buffer in place using GCHandle.Allocate(object, GCHandleType.Pinned);

static extern MMRESULT waveInUnprepareHeader(IntPtr hwi, ref WAVEHDR pwh, uint cbwh);

Shared Function waveInUnprepareHeader(<MarshalAs(UnmanagedType.I4)> ByVal hwi As Integer, ByRef pwh As WAVEHDR, ByVal cbwh As UInteger) As MMRESULT

WAVEHDR

The same WAVEHDR structure used with waveOutPrepareHeader() is also used with

audio driver will asynchronously set the WHDR_DONE bit in WAVEHDR.dwflags when

This means that the WAVEHDR struct passed to the waveOutWrite() function must be

    waveHdrPtr = Marshal.AllocHGlobal(Marshal.SizeOf(waveHdr));

    waveHdr.lpData = wavedata;  // audio buffer

    waveHdr.dwBufferLength = wf.nSamplesPerSec * wf.nBlockAlign;  // it's size

    waveHdr.dwFlags = 0;    // clear before waveOutPrepareHeader()

    Marshal.StructureToPtr(waveHdr, waveHdrPtr, true);    // copy to unmanaged memory

    if ((MMRESULT = waveOutPrepareHeader(waveDevice, waveHdrPtr, Marshal.SizeOf(waveHdr))) != MMSYSERR_NOERROR)

    WAVEHDR wh = (WAVEHDR)Marshal.PtrToStructure(waveHdrPtr, typeof(WAVEHDR));  // copy struct back from unmanaged memory

    waveHdr = wh;  // reset managed struct

    waveHdr.dwFlags |= (WHDR_BEGINLOOP | WHDR_ENDLOOP);  // add the looping flag bits

    waveHdr.dwLoops = MINUS_ONE; ;

    Marshal.StructureToPtr(waveHdr, waveHdrPtr, true);   // and update the unmanaged struct.

    if ((MMRESULT = waveOutWrite(waveDevice, waveHdrPtr, Marshal.SizeOf(waveHdr))) != MMSYSERR_NOERROR)

    while ((waveHdr.dwFlags & WHDR_DONE) == 0)  // wait for it

       WAVEHDR wh = (WAVEHDR)Marshal.PtrToStructure(waveHdrPtr, typeof(WAVEHDR)); // copy unmanaged struct

       waveHdr = wh;  // update managed struct

    if ((MMRESULT = waveOutUnprepareHeader(waveDevice, waveHdrPtr, Marshal.SizeOf(waveHdr))) != MMSYSERR_NOERROR)

        Marshal.FreeHGlobal(waveHdrPtr);

public static extern uint waveOutUnprepareHeader(IntPtr hwo,ref WAVEHDR pwh,uint cbwh);

public static extern uint waveOutWrite(IntPtr hwo, ref WAVEHDR pwh, uint cbwh);

enum WaveHdrFlags : uint

Enum WaveHdrFlags As UInteger