The members of the DMUS_SEGF_FLAGS enumeration are passed to various methods of IDirectMusicPerformance in order to control the timing and other aspects of actions on a segment.
typedef enum enumDMUS_SEGF_FLAGS {
    DMUS_SEGF_REFTIME          = 64,
    DMUS_SEGF_SECONDARY        = 128,
    DMUS_SEGF_QUEUE            = 256,
    DMUS_SEGF_CONTROL          = 512
    DMUS_SEGF_AFTERPREPARETIME = 1<<10,
    DMUS_SEGF_GRID             = 1<<11,
    DMUS_SEGF_BEAT             = 1<<12,
    DMUS_SEGF_MEASURE          = 1<<13,
    DMUS_SEGF_DEFAULT          = 1<<14,
    DMUS_SEGF_NOINVALIDATE     = 1<<15,
} DMUS_SEGF_FLAGS;
 Normally the primary segment is the control segment. The DMUS_SEGF_CONTROL flag can be used to make a secondary segment the control segment. There should be only one control segment at a time. (It is possible to create multiple control segments, but there is no guarantee of which one will actually be used by DirectMusic as the control segment.) When a track calls GetParam on a another track, it does so on the control segment. Also, by default only the control segment sends tempo messages.
If the DMUS_SEGF_CONTROL flag is set, DMUS_SEGF_SECONDARY is assumed.
  Windows NT/2000: Requires Windows 2000.
  Windows 95/98: Requires Windows 95 or later. Available as a redistributable for Windows 95.
  Header: Declared in dmusici.h.
IDirectMusicPerformance::Invalidate, IDirectMusicPerformance::PlaySegment, IDirectMusicPerformance::Stop, IDirectMusicSegment::GetDefaultResolution, IDirectMusicSegment::SetDefaultResolution, DMUS_TIME_RESOLVE_FLAGS