MIDIHDR structure

The MIDIHDR structure defines the header used to identify a MIDI system-exclusive or stream buffer.

Syntax

typedef struct midihdr_tag {
  LPSTR              lpData;
  DWORD              dwBufferLength;
  DWORD              dwBytesRecorded;
  DWORD_PTR          dwUser;
  DWORD              dwFlags;
  struct midihdr_tag  *lpNext;
  DWORD_PTR          reserved;
  DWORD              dwOffset;
  DWORD_PTR          dwReserved[4];
} MIDIHDR, *LPMIDIHDR;

Members

• lpData
  Pointer to MIDI data.

• dwBufferLength
  Size of the buffer.

• dwBytesRecorded
  Actual amount of data in the buffer. This value should be less than or equal to the value given in the dwBufferLength member.

• dwUser
  Custom user data.

• dwFlags
  Flags giving information about the buffer.

  Name	Description
  MHDR_DONE	Set by the device driver to indicate that it is finished with the buffer and is returning it to the application.
  MHDR_INQUEUE	Set by Windows to indicate that the buffer is queued for playback.
  MHDR_ISSTRM	Set to indicate that the buffer is a stream buffer.
  MHDR_PREPARED	Set by Windows to indicate that the buffer has been prepared by using the midiInPrepareHeader or midiOutPrepareHeader function.

   

• lpNext
  Reserved; do not use.

• reserved
  Reserved; do not use.

• dwOffset
  Offset into the buffer when a callback is performed. (This callback is generated because the MEVT_F_CALLBACK flag is set in the dwEvent member of the MIDIEVENT structure.) This offset enables an application to determine which event caused the callback.

• dwReserved
  Reserved; do not use.

Requirements

See also

Musical Instrument Digital Interface (MIDI)

MIDI Structures

MIDIEVENT

midiInPrepareHeader

midiOutPrepareHeader

MIDI Structures