Request message structure.

typedef struct DSRequestMsg {
 DS_MSG_HEADER

union {
 struct {
  DSDataType dataType;
  Item subscriberPort;
  } subscribe;

 struct {
  DSDataType exemptStream;
  unsigned long nowTime;
  } clockSync;

 struct {
  unsigned long markerValue;
  unsigned long options;
  } goMarker;

 struct {
  DSDataType streamType;
  long channelNumber;
  long* channelStatusPtr;
  } getChannel;

 struct {
  DSDataType streamType;
  long channelNumber;
  long channelStatus;
  } setChannel;

 struct {
  DSDataType streamType;
  long userDefinedOpcode;
  void* userDefinedArgPtr;
  } control;

 struct {
  Item acquirePort;
  } connect;

 struct {
  unsigned long options;
  } start;

 struct {
  unsigned long options;
  } stop;

 } msg;

} DSRequestMsg, *DSRequestMsgPtr

Messages sent to the streamer by the application to control stream flow and parameters.

• dataType 4 byte ASCII data type identifier.

• subscriberPort Message port to send data to.

• exemptStream Stream that sync message should not be sent to.

• nowTime Time value to propagate to everyone.

• markerValue Place to “branch” to in the stream.

• options Options for branching.

• streamType Which subscriber.

• channelNumber Logical data channel.

• channelStatusPtr Place to return channel status.

• streamType Which subscriber.

• channelNumber Logical data channel.

• channelStatus Channel status bits to set.

• streamType Subscriber to send control message to.

• userDefinedOpcode Subscriber defined action code.

• userDefinedArgPtr Subscriber defined argument.

• acquirePort Connect this data port to stream.

• options Start options.

• options Stop options.

DataStream.h