# DSIsMarker

Checks the current stream position.

### Synopsis

`int32 DSIsMarker (DSStreamCBPtr streamCBPtr, uint32 markerValue, Boolean* fIsMarker)`

### Description

Determines if the specified stream is positioned at the destination of a stream branching operation because it arrived there as the result of a `DSGoMarker()` call. This is used to implement conditional flushing of data based upon the knowledge that the stream position is a result of "play through" or a "branch."

### Arguments

`streamCBPtr`
  Pointer to the stream context block.

`markerValue`
  Pointer to Boolean where `TRUE` is returned if markerValue is a branch destination.

`fIsMarker`
  Pointer to a Boolean variable that will be set to `TRUE` if the value of `markerValue` is the destination of the most recent `DSGoMarker()` call.

### Return Value

Value
  Error Condition

`kDSNoErr`
  None

The return value is not dependent on whether or not the stream is located at the specified marker.

### Associated Files

DataStreamLib.h

### See Also

`DSGoMarker`