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MIDIHDR structure (mmeapi.h)

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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[8];
} MIDIHDR, *PMIDIHDR, *NPMIDIHDR, *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[8]

Reserved; do not use.

Requirements

Requirement Value
Minimum supported client Windows 2000 Professional [desktop apps only]
Minimum supported server Windows 2000 Server [desktop apps only]
Header mmeapi.h (include Windows.h)

See also

MIDI Structures

MIDIEVENT

Musical Instrument Digital Interface (MIDI)

midiInPrepareHeader

midiOutPrepareHeader