EMA C++ RDM Usage Guide : 9 Market Maker Domain : 9.2 Usage
 
9.2 Usage
9.2.1 Market Maker Request Message
A Market Maker request message is encoded using ReqMsg and sent by Open Message Model consumer applications. The request specifies the name of an item in which the consumer is interested.
To receive updates, a consumer can make a “streaming” request by setting the ReqMsg.InterestAfterRefresh to true. If the flag is not set, the consumer requests a “snapshot,” and the final part of the refresh indicates all responses have been received for the snapshot. Updates may be received in either case if the refresh has multiple parts.
To stop updates, a consumer can pause an item (if the provider supports this functionality). For more information, refer to the Enterprise Message API C++ Edition Developers Guide.
 
Table 61: Market Maker Request Message  
COMPONENT
DESCRIPTION / VALUE
DomainType
Required. MMT_MARKET_MAKER = 9
Interactions
Conditional. Use the appropriate interactions according to your messaging needs:
InitialImage: true, indicates that an initial image is required.
InterestAfterRefresh: true, indicates that a streaming request is required.
Pause: true, indicates that a pause is required.
Indications
Optional.
ConflatedInUpdates: true, indicates that conflated updates are required.
Batch and View request are specified in the Payload.
QoS
Optional. Indicates the QoS at which the consumer wants the stream serviced. If both QoS and worstQos are specified, this request can be satisfied by a range of QoS.
worstQos
Optional. Used with QoS to define a range of acceptable QoS. If the provider encounters such a range, it should attempt to provide the best possible QoS within that range.
This should only be used on services that claim to support it via the SupportsQosRange item in the Source Directory response (for details, refer to Section 4.3.1.1).
NOTE: Enterprise Message API provides the Request.Qos() method to set both Qos and WorstQos depending upon the timeliness and rate values.
Priority
Optional. Indicates the class and count associated with stream priority.
extendedHeader
Not used.
ServiceName
Required. Specifies the name of the service from which the consumer wishes to request the item.
NOTE: The consumer application should set either the ServiceName or ServiceId of the service, but not both.
ServiceId
Required. Specifies the ID of the service that provides the requested item.
NOTE: The consumer application should set either the ServiceName or ServiceId of the service, but not both.
NameType
Optional. When consuming from LSEG sources, NameType is typically set to INSTRUMENT_NAME_RIC = 1 (the “Instrument Code”). If absent, its value reverts to the default, which is INSTRUMENT_NAME_RIC = 1.
Name
Required. Specifies the name of the requested item.
NOTE: Not used for Batch Item request.
Filter
Not used.
Identifier
Not used.
Attrib
Not used.
Payload
Optional. When features such as View or Batch are leveraged, the payload can contain information relevant to that feature. For more details, refer to Appendix A.