Migration Guide for Messaging API Changes

What Changed

The messaging API was reorganized so the market data domain API and the message decoding API are separated more clearly.

The important mechanical rules are:

• Messaging primitives, SBE messages, fields, composites, serialization helpers, decimals, timestamps, and string references moved from OnixS::CME::MDH to OnixS::CME::MDH::Messaging.
• Tag-based FIX support moved from OnixS::CME::MDH::FIX to OnixS::CME::MDH::Messaging::FIX.
• Old messaging headers still compile while compatibility mode is enabled, but they are deprecated forwarding headers.
• Define ONIXS_CMEMDH_ENABLE_DEPRECATED_WARNING to get warnings about deprecated API usage.
• <OnixS/CME/MDH.h> includes compatibility declarations by default. Define ONIXS_CMEMDH_MESSAGING_NO_DEPRECATED only for the final hard-cutover validation build.
• Listener argument aliases mostly remain in OnixS::CME::MDH, but the message types they wrap now come from Messaging.
• To also exclude older deprecated non-messaging API members, define ONIXS_CMEMDH_NO_DEPRECATED.

For migrated code, local namespace aliases usually keep call sites readable:

namespace MDH = OnixS::CME::MDH;
namespace Msg = OnixS::CME::MDH::Messaging;
namespace FIX = OnixS::CME::MDH::Messaging::FIX;

Recommended migration flow:

1. Upgrade the SDK.
2. Add ONIXS_CMEMDH_ENABLE_DEPRECATED_WARNING macro before including OnixS headers.
3. Build with deprecation diagnostics enabled, for example -Wdeprecated-declarations with GCC/Clang or /W3 or higher with MSVC.
4. Replace old headers, old top-level messaging names, and old FIX:: references using the mapping tables below.
5. Fix the non-mechanical changes: tryCast, StrRef::items(), listener aliases, and value-sensitive tag renames.
6. Add ONIXS_CMEMDH_MESSAGING_NO_DEPRECATED macro before including OnixS headers.
7. Perform a separate validation build once deprecated names are gone.

Mapping Tables

Use these tables as the searchable migration reference. The old names are available only through deprecated compatibility declarations.

Headers

Old header	New header
<OnixS/CME/MDH/CppUtils.h>	<OnixS/CME/MDH/ABI.h>
<OnixS/CME/MDH/Messages.h>	<OnixS/CME/MDH/messaging/Messages.h>
<OnixS/CME/MDH/Fields.h>	<OnixS/CME/MDH/messaging/Fields.h>
<OnixS/CME/MDH/Composites.h>	<OnixS/CME/MDH/messaging/Composites.h>
<OnixS/CME/MDH/Decimal.h>	<OnixS/CME/MDH/messaging/Decimal.h> and <OnixS/CME/MDH/messaging/Decimal.Operations.h>
<OnixS/CME/MDH/Time.h>	<OnixS/CME/MDH/messaging/Time.h>
<OnixS/CME/MDH/String.h>	<OnixS/CME/MDH/messaging/String.h> and <OnixS/CME/MDH/messaging/StrRef.h>
<OnixS/CME/MDH/Integral.h>	<OnixS/CME/MDH/messaging/Integral.h>
<OnixS/CME/MDH/Memory.h>	<OnixS/CME/MDH/messaging/Memory.h>
<OnixS/CME/MDH/Serialization.h>	<OnixS/CME/MDH/messaging/Serialization.h>
<OnixS/CME/MDH/BinaryMessage.h>	<OnixS/CME/MDH/messaging/SbeMessage.h>
<OnixS/CME/MDH/SchemaTraits.h>	<OnixS/CME/MDH/messaging/SchemaTraits.h>
<OnixS/CME/MDH/Typification.h>	<OnixS/CME/MDH/messaging/Typification.h>
<OnixS/CME/MDH/FIX/Accessors.h>	<OnixS/CME/MDH/Accessors.h>
<OnixS/CME/MDH/FIX/Field.h>	<OnixS/CME/MDH/messaging/TagBased/Field.h>
<OnixS/CME/MDH/FIX/Message.h>	<OnixS/CME/MDH/messaging/TagBased/Message.h>
<OnixS/CME/MDH/FIX/Messages.h>	<OnixS/CME/MDH/messaging/TagBased/Messages.h>
<OnixS/CME/MDH/FIX/Tags.h>	<OnixS/CME/MDH/messaging/TagBased/Tags.h>
<OnixS/CME/MDH/FIX/Tag.h>	<OnixS/CME/MDH/messaging/TagBased/Tag.h>
<OnixS/CME/MDH/FIX/MessageListener.h>	<OnixS/CME/MDH/messaging/TagBased/MessageListener.h>
<OnixS/CME/MDH/FIX/MultiContainer.h>	<OnixS/CME/MDH/messaging/TagBased/MultiContainer.h>
<OnixS/CME/MDH/FIX/ValueContainer.h>	<OnixS/CME/MDH/messaging/TagBased/ValueContainer.h>
<OnixS/CME/MDH/FIX/ValueConverters.h>	<OnixS/CME/MDH/messaging/TagBased/ValueConverters.h>

For broad includes, use either:

#include <OnixS/CME/MDH.h>
#include <OnixS/CME/MDH/Messaging.h>

Types and APIs

Old name	New name
Char	Messaging::Char
CHAR	Messaging::CHAR
Int8	Messaging::Int8
UInt8	Messaging::UInt8
Int16	Messaging::Int16
UInt16	Messaging::UInt16
Int32	Messaging::Int32
UInt32	Messaging::UInt32
Int64	Messaging::Int64
UInt64	Messaging::UInt64
IntegralConstant<Type, Constant>	Messaging::IntegralConstant<Type, Constant>
UnwrapType<Type>	Messaging::UnwrapType<Type>
LocalMktDate	Messaging::LocalMktDate
Asset	Messaging::Char[6]
CFICode	Messaging::Char[6]
CountryCode	Messaging::Char[2]
Currency	Messaging::Char[3]
FeedType	Messaging::Char[3]
LongName	Messaging::Char[35]
QuoteReqId	Messaging::Char[23]
SecurityExchange	Messaging::Char[4]
SecurityGroup	Messaging::Char[6]
SecuritySubType	Messaging::Char[5]
SecurityType	Messaging::Char[6]
String3	Messaging::Char[3]
String5	Messaging::Char[5]
String6	Messaging::Char[6]
String7	Messaging::Char[7]
String8	Messaging::Char[8]
String12	Messaging::Char[12]
String20	Messaging::Char[20]
String25	Messaging::Char[25]
Symbol	Messaging::Char[20]
Text	Messaging::Char[180]
UnderlyingSymbol	Messaging::Char[20]
UnitOfMeasure	Messaging::Char[30]
UserDefinedInstrument	Messaging::UserDefinedInstrument
StrRef	Messaging::StrRef
toStrRef(...)	Messaging::toStrRef(...)
toStr(...) for messaging values	Messaging::toStr(...)
Decimal	Messaging::Decimal
FloatingPointDecimal<MantissaType, ExponentType>	Messaging::FloatingPointDecimal<MantissaType, ExponentType>
FixedPointDecimal<MantissaType, ExponentType>	Messaging::FixedPointDecimal<MantissaType, ExponentType>
DecimalMantissa	Messaging::DecimalMantissa
DecimalExponent	Messaging::DecimalExponent
TimeTraits	Messaging::TimeTraits
TimeSpanFormat	Messaging::TimeSpanFormat
TimeSpan	Messaging::TimeSpan
Month	Messaging::Month
TimestampFormat	Messaging::TimestampFormat
Timestamp	Messaging::Timestamp
Byte	Messaging::Byte
Word	Messaging::Word
DWord	Messaging::DWord
QWord	Messaging::QWord
MessageSize	Messaging::MessageSize
CompositeExtractor<Size>	Messaging::CompositeExtractor<Size>
MessageTemplateId	Messaging::MessageTemplateId
BinaryBlockBase	Messaging::BinaryBlockBase
BinaryMessage	Messaging::SbeMessage
BinaryBlock<Container, BlockLength>	Messaging::BinaryBlock<Container, BlockLength>
SbeFields<Container, BlockLength>	Messaging::SbeFields<Container, BlockLength>
BinaryGroupEntry<Length>	Messaging::SbeGroupEntry<Length>
BinaryGroupEntries<EntryType, Length, NumInGroup, EncodedLength>	Messaging::SbeGroupEntries<EntryType, Length, NumInGroup, EncodedLength>
BinaryGroup<EntryType, DimensionType, LengthType>	Messaging::SbeGroup<EntryType, DimensionType, LengthType>
BinaryGroups<Length>	Messaging::SbeGroupList<Length>
SchemaVersion	Messaging::SchemaVersion
SchemaTraits	Messaging::SchemaTraits
Decimal9	Messaging::Decimal9
NullDecimal9	Messaging::NullDecimal9
DecimalQty	Messaging::DecimalQty
NullDecimalQty	Messaging::NullDecimalQty
MaturityMonthYear	Messaging::MaturityMonthYear
NullMaturityMonthYear	Messaging::NullMaturityMonthYear
PRICE9	Messaging::PRICE9
NullPRICE9	Messaging::NullPRICE9
GroupSize	Messaging::GroupSize
GroupSize8Byte	Messaging::GroupSize8Byte
GroupSizeEncoding	Messaging::GroupSizeEncoding
MessageHeader	Messaging::MessageHeader
MessageHeaderBuilder	Messaging::MessageHeaderBuilder
InstAttribType	Messaging::InstAttribType
EntryTypeChannelReset	Messaging::EntryTypeChannelReset
EntryTypeLimits	Messaging::EntryTypeLimits
EntryTypeTrade	Messaging::EntryTypeTrade
EntryTypeVol	Messaging::EntryTypeVol
UpdateActionNew	Messaging::UpdateActionNew
UpdateTypeNew	Messaging::UpdateTypeNew
SecurityAltIDSourceISIN	Messaging::SecurityAltIDSourceISIN
SecurityIDSource	Messaging::SecurityIDSource
AggressorFlag	Messaging::AggressorFlag
AggressorSide	Messaging::AggressorSide
EventType	Messaging::EventType
HaltReason	Messaging::HaltReason
LegSide	Messaging::LegSide
EntryType	Messaging::EntryType
EntryTypeBook	Messaging::EntryTypeBook
EntryTypeDailyStatistics	Messaging::EntryTypeDailyStatistics
EntryTypeStatistics	Messaging::EntryTypeStatistics
UpdateAction	Messaging::UpdateAction
MoneyOrPar	Messaging::MoneyOrPar
OpenCloseSettlFlag	Messaging::OpenCloseSettlFlag
OrderUpdateAction	Messaging::OrderUpdateAction
PriceSource	Messaging::PriceSource
PutOrCall	Messaging::PutOrCall
RepoSubType	Messaging::RepoSubType
SecurityAltIDSource	Messaging::SecurityAltIDSource
SecurityTradingEvent	Messaging::SecurityTradingEvent
SecurityTradingStatus	Messaging::SecurityTradingStatus
SecurityUpdateAction	Messaging::SecurityUpdateAction
Side	Messaging::Side
WorkupTradingStatus	Messaging::WorkupTradingStatus
InstAttribValue	Messaging::InstAttribValue
MatchEventIndicator	Messaging::MatchEventIndicator
SettlPriceType	Messaging::SettlPriceType
NullInt32	Messaging::NullInt32
NullInt8	Messaging::NullInt8
NullLocalMktDate	Messaging::NullLocalMktDate
NullUInt16	Messaging::NullUInt16
NullUInt32	Messaging::NullUInt32
NullUInt64	Messaging::NullUInt64
NullUInt8	Messaging::NullUInt8
InstrumentDefinitionFixedIncome57	Messaging::InstrumentDefinitionFixedIncome57
InstrumentDefinitionFX63	Messaging::InstrumentDefinitionFX63
IncrementalRefreshBookLongQty64	Messaging::IncrementalRefreshBookLongQty64
IncrementalRefreshTradeSummaryLongQty65	Messaging::IncrementalRefreshTradeSummaryLongQty65
IncrementalRefreshVolumeLongQty66	Messaging::IncrementalRefreshVolumeLongQty66
IncrementalRefreshSessionStatisticsLongQty67	Messaging::IncrementalRefreshSessionStatisticsLongQty67
SnapshotFullRefreshLongQty69	Messaging::SnapshotFullRefreshLongQty69
AdminLogin408	Messaging::AdminLogin408
AdminLogout409	Messaging::AdminLogout409
AdminHeartbeat410	Messaging::AdminHeartbeat410
ChannelReset4	Messaging::ChannelReset4
AdminHeartbeat12	Messaging::AdminHeartbeat12
AdminLogin15	Messaging::AdminLogin15
AdminLogout16	Messaging::AdminLogout16
InstrumentDefinitionFuture54	Messaging::InstrumentDefinitionFuture54
InstrumentDefinitionSpread56	Messaging::InstrumentDefinitionSpread56
SecurityStatus30	Messaging::SecurityStatus30
IncrementalRefreshBook46	Messaging::IncrementalRefreshBook46
IncrementalRefreshDailyStatistics49	Messaging::IncrementalRefreshDailyStatistics49
IncrementalRefreshLimitsBanding50	Messaging::IncrementalRefreshLimitsBanding50
IncrementalRefreshSessionStatistics51	Messaging::IncrementalRefreshSessionStatistics51
IncrementalRefreshVolume37	Messaging::IncrementalRefreshVolume37
SnapshotFullRefresh52	Messaging::SnapshotFullRefresh52
QuoteRequest39	Messaging::QuoteRequest39
InstrumentDefinitionOption55	Messaging::InstrumentDefinitionOption55
IncrementalRefreshTradeSummary48	Messaging::IncrementalRefreshTradeSummary48
IncrementalRefreshOrderBook47	Messaging::IncrementalRefreshOrderBook47
SnapshotFullRefreshOrderBook53	Messaging::SnapshotFullRefreshOrderBook53
FIX::Tag	Messaging::FIX::Tag
FIX::MessageArgs	Messaging::FIX::MessageArgs
FIX::MessageListener	Messaging::FIX::MessageListener
FIX::TagValue	Messaging::FIX::TagValue
FIX::TagValues	Messaging::FIX::TagValues
FIX::TagValueIterator	Messaging::FIX::TagValueIterator
FIX::TagValueConstIterator	Messaging::FIX::TagValueConstIterator
FIX::TagValueSelector	Messaging::FIX::TagValueSelector
FIX::TagValueSelectionIterator	Messaging::FIX::TagValueSelectionIterator
FIX::MultiContainer	Messaging::FIX::MultiContainer
FIX::ValueConverter	Messaging::FIX::ValueConverter
FIX::NullConverter	Messaging::FIX::NullConverter
FIX::StrRefConverter	Messaging::FIX::StrRefConverter
FIX::CharConverter	Messaging::FIX::CharConverter
FIX::IntegerConverter<Integer, Descendant>	Messaging::FIX::IntegerConverter<Integer, Descendant>
FIX::Int8Converter	Messaging::FIX::Int8Converter
FIX::UInt8Converter	Messaging::FIX::UInt8Converter
FIX::Int16Converter	Messaging::FIX::Int16Converter
FIX::UInt16Converter	Messaging::FIX::UInt16Converter
FIX::Int32Converter	Messaging::FIX::Int32Converter
FIX::UInt32Converter	Messaging::FIX::UInt32Converter
FIX::Int64Converter	Messaging::FIX::Int64Converter
FIX::UInt64Converter	Messaging::FIX::UInt64Converter
FIX::DecimalConverter	Messaging::FIX::DecimalConverter
FIX::TimestampConverter	Messaging::FIX::TimestampConverter
FIX::MaturityMonthYearConverter	Messaging::FIX::MaturityMonthYearConverter
FIX::ValueKinds	Messaging::FIX::ValueKinds
FIX::ValueKind<Value>	Messaging::FIX::ValueKind<Value>
FIX::ValueConversionTraits<Value, Kind>	Messaging::FIX::ValueConversionTraits<Value, Kind>
FIX::ValueConversion<Value>	Messaging::FIX::ValueConversion<Value>
FIX::ValueContainer	Messaging::FIX::ValueContainer
FIX::Field	Messaging::FIX::Field
FIX::FieldAccessor	Messaging::FIX::FieldAccessor
FIX::FieldSet	Messaging::FIX::FieldSet
FIX::GroupEntrySource	Messaging::FIX::GroupEntrySource
FIX::GroupEntryAccessor	Messaging::FIX::GroupEntryAccessor
FIX::GroupEntry	Messaging::FIX::GroupEntry
FIX::GroupEntriesSource	Messaging::FIX::GroupEntriesSource
FIX::Group	Messaging::FIX::Group
FIX::MessageAccessor	Messaging::FIX::MessageAccessor
FIX::Message	Messaging::FIX::Message
FIX::ChannelReset4	Messaging::FIX::ChannelReset4
FIX::AdminHeartbeat12	Messaging::FIX::AdminHeartbeat12
FIX::AdminLogin15	Messaging::FIX::AdminLogin15
FIX::AdminLogout16	Messaging::FIX::AdminLogout16
FIX::SecurityStatus30	Messaging::FIX::SecurityStatus30
FIX::IncrementalRefreshVolume37	Messaging::FIX::IncrementalRefreshVolume37
FIX::QuoteRequest39	Messaging::FIX::QuoteRequest39
FIX::IncrementalRefreshBook46	Messaging::FIX::IncrementalRefreshBook46
FIX::IncrementalRefreshOrderBook47	Messaging::FIX::IncrementalRefreshOrderBook47
FIX::IncrementalRefreshTradeSummary48	Messaging::FIX::IncrementalRefreshTradeSummary48
FIX::IncrementalRefreshDailyStatistics49	Messaging::FIX::IncrementalRefreshDailyStatistics49
FIX::IncrementalRefreshLimitsBanding50	Messaging::FIX::IncrementalRefreshLimitsBanding50
FIX::IncrementalRefreshSessionStatistics51	Messaging::FIX::IncrementalRefreshSessionStatistics51
FIX::SnapshotFullRefresh52	Messaging::FIX::SnapshotFullRefresh52
FIX::SnapshotFullRefreshOrderBook53	Messaging::FIX::SnapshotFullRefreshOrderBook53
FIX::InstrumentDefinitionFuture54	Messaging::FIX::InstrumentDefinitionFuture54
FIX::InstrumentDefinitionOption55	Messaging::FIX::InstrumentDefinitionOption55
FIX::InstrumentDefinitionSpread56	Messaging::FIX::InstrumentDefinitionSpread56
FIX::InstrumentDefinitionFixedIncome57	Messaging::FIX::InstrumentDefinitionFixedIncome57
FIX::InstrumentDefinitionFX63	Messaging::FIX::InstrumentDefinitionFX63
FIX::IncrementalRefreshBookLongQty64	Messaging::FIX::IncrementalRefreshBookLongQty64
FIX::IncrementalRefreshTradeSummaryLongQty65	Messaging::FIX::IncrementalRefreshTradeSummaryLongQty65
FIX::IncrementalRefreshVolumeLongQty66	Messaging::FIX::IncrementalRefreshVolumeLongQty66
FIX::IncrementalRefreshSessionStatisticsLongQty67	Messaging::FIX::IncrementalRefreshSessionStatisticsLongQty67
FIX::SnapshotFullRefreshLongQty69	Messaging::FIX::SnapshotFullRefreshLongQty69
FIX::AdminLogin408	Messaging::FIX::AdminLogin408
FIX::AdminLogout409	Messaging::FIX::AdminLogout409
FIX::AdminHeartbeat410	Messaging::FIX::AdminHeartbeat410
FIX::securityId(...)	securityId(...)
FIX::securityGroup(...)	securityGroup(...)
FIX::symbol(...)	symbol(...)
FIX::asset(...)	asset(...)
FIX::securityUpdateAction(...)	securityUpdateAction(...)
FIX::bookDepths(...)	bookDepths(...)
FIX::matchEventIndicator(...)	matchEventIndicator(...)
FIX::timestamp(...)	timestamp(...)

ChannelId and SecurityId are domain identifiers, not moved messaging API names. They remain in OnixS::CME::MDH, but their underlying typedefs now use messaging primitives:

Domain typedef	Underlying type
ChannelId	Messaging::UInt32
SecurityId	Messaging::Int32

Most code should keep using ChannelId and SecurityId. Code that stores the underlying type directly, performs overload selection on it, or mirrors callback signatures may need Messaging::UInt32 or Messaging::Int32.

Tag Constants

This is the complete deprecated old-to-new tag mapping from the include/OnixS/CME/MDH/FIX/Tags.h compatibility shim. Use it as the authoritative reference when replacing old FIX::Tags::* constants.

Old tag	New tag	Value
FIX::Tags::AggressorSide	Messaging::FIX::Tags::AggressorSide	5797
FIX::Tags::AltMinPriceIncrement	Messaging::FIX::Tags::AltMinPriceIncrement	37739
FIX::Tags::AltMinQuoteLife	Messaging::FIX::Tags::AltMinQuoteLife	37738
FIX::Tags::AltPriceIncrementConstraint	Messaging::FIX::Tags::AltPriceIncrementConstraint	37742
FIX::Tags::ApplID	Messaging::FIX::Tags::ApplId	1180
FIX::Tags::Asset	Messaging::FIX::Tags::Asset	6937
FIX::Tags::CFICode	Messaging::FIX::Tags::CfiCode	461
FIX::Tags::ClearedVolume	Messaging::FIX::Tags::ClearedVolume	5791
FIX::Tags::ContractMultiplier	Messaging::FIX::Tags::ContractMultiplier	231
FIX::Tags::ContractMultiplierUnit	Messaging::FIX::Tags::ContractMultiplierUnit	1435
FIX::Tags::CountryOfIssue	Messaging::FIX::Tags::CountryOfIssue	470
FIX::Tags::CouponDayCount	Messaging::FIX::Tags::CouponDayCount	1950
FIX::Tags::CouponFrequencyPeriod	Messaging::FIX::Tags::CouponFrequencyPeriod	1948
FIX::Tags::CouponFrequencyUnit	Messaging::FIX::Tags::CouponFrequencyUnit	1949
FIX::Tags::CouponRate	Messaging::FIX::Tags::CouponRate	223
FIX::Tags::Currency	Messaging::FIX::Tags::Currency	15
FIX::Tags::CurrentChunk	Messaging::FIX::Tags::CurrentChunk	37710
FIX::Tags::DatedDate	Messaging::FIX::Tags::DatedDate	873
FIX::Tags::DecayQuantity	Messaging::FIX::Tags::DecayQuantity	5818
FIX::Tags::DecayStartDate	Messaging::FIX::Tags::DecayStartDate	5819
FIX::Tags::DisplayFactor	Messaging::FIX::Tags::DisplayFactor	9787
FIX::Tags::EventTime	Messaging::FIX::Tags::EventTime	1145
FIX::Tags::EventType	Messaging::FIX::Tags::EventType	865
FIX::Tags::FXBenchmarkRateFix	Messaging::FIX::Tags::FxBenchmarkRateFix	2796
FIX::Tags::FXCurrencySymbol	Messaging::FIX::Tags::FxCurrencySymbol	37725
FIX::Tags::FinancialInstrumentFullName	Messaging::FIX::Tags::FinancialInstrumentFullName	2714
FIX::Tags::FixRateLocalTime	Messaging::FIX::Tags::FixRateLocalTime	37726
FIX::Tags::FixRateLocalTimeZone	Messaging::FIX::Tags::FixRateLocalTimeZone	37727
FIX::Tags::FlowScheduleType	Messaging::FIX::Tags::FlowScheduleType	1439
FIX::Tags::HaltReason	Messaging::FIX::Tags::HaltReason	327
FIX::Tags::HeartBtInt	Messaging::FIX::Tags::HeartBtInt	108
FIX::Tags::HighLimitPrice	Messaging::FIX::Tags::HighLimitPrice	1149
FIX::Tags::InstAttribType	Messaging::FIX::Tags::InstAttribType	871
FIX::Tags::InstAttribValue	Messaging::FIX::Tags::InstAttribValue	872
FIX::Tags::InstrumentGUID	Messaging::FIX::Tags::InstrumentGUId	37513
FIX::Tags::InterveningDays	Messaging::FIX::Tags::InterveningDays	37730
FIX::Tags::IssueDate	Messaging::FIX::Tags::IssueDate	225
FIX::Tags::Issuer	Messaging::FIX::Tags::Issuer	106
FIX::Tags::LastMsgSeqNumProcessed	Messaging::FIX::Tags::LastMsgSeqNumProcessed	369
FIX::Tags::LastQty	Messaging::FIX::Tags::LastQty	32
FIX::Tags::LastUpdateTime	Messaging::FIX::Tags::LastUpdateTime	779
FIX::Tags::LegOptionDelta	Messaging::FIX::Tags::LegOptionDelta	1017
FIX::Tags::LegPrice	Messaging::FIX::Tags::LegPrice	566
FIX::Tags::LegRatioQty	Messaging::FIX::Tags::LegRatioQty	623
FIX::Tags::LegSecurityID	Messaging::FIX::Tags::LegSecurityId	602
FIX::Tags::LegSecurityIDSource	Messaging::FIX::Tags::LegSecurityIdSource	603
FIX::Tags::LegSide	Messaging::FIX::Tags::LegSide	624
FIX::Tags::LotType	Messaging::FIX::Tags::LotType	1093
FIX::Tags::LowLimitPrice	Messaging::FIX::Tags::LowLimitPrice	1148
FIX::Tags::MDDisplayQty	Messaging::FIX::Tags::DisplayQty	37706
FIX::Tags::MDEntryPx	Messaging::FIX::Tags::EntryPx	270
FIX::Tags::MDEntrySize	Messaging::FIX::Tags::EntrySize	271
FIX::Tags::MDEntryType	Messaging::FIX::Tags::EntryType	269
FIX::Tags::MDFeedType	Messaging::FIX::Tags::FeedType	1022
FIX::Tags::MDOrderPriority	Messaging::FIX::Tags::OrderPriority	37707
FIX::Tags::MDPriceLevel	Messaging::FIX::Tags::PriceLevel	1023
FIX::Tags::MDSecurityTradingStatus	Messaging::FIX::Tags::MdSecurityTradingStatus	1682
FIX::Tags::MDTradeEntryID	Messaging::FIX::Tags::TradeEntryId	37711
FIX::Tags::MDUpdateAction	Messaging::FIX::Tags::UpdateAction	279
FIX::Tags::MainFraction	Messaging::FIX::Tags::MainFraction	37702
FIX::Tags::MarketDepth	Messaging::FIX::Tags::MarketDepth	264
FIX::Tags::MarketSegmentID	Messaging::FIX::Tags::MarketSegmentId	1300
FIX::Tags::MarketSet	Messaging::FIX::Tags::MarketSet	37722
FIX::Tags::MatchAlgorithm	Messaging::FIX::Tags::MatchAlgorithm	1142
FIX::Tags::MatchEventIndicator	Messaging::FIX::Tags::MatchEventIndicator	5799
FIX::Tags::MaturityDate	Messaging::FIX::Tags::MaturityDate	541
FIX::Tags::MaturityMonthYear	Messaging::FIX::Tags::MaturityMonthYear	200
FIX::Tags::MaxBidAskConstraint	Messaging::FIX::Tags::MaxBidAskConstraint	37743
FIX::Tags::MaxPriceDiscretionOffset	Messaging::FIX::Tags::MaxPriceDiscretionOffset	37728
FIX::Tags::MaxPriceVariation	Messaging::FIX::Tags::MaxPriceVariation	1143
FIX::Tags::MaxTradeVol	Messaging::FIX::Tags::MaxTradeVol	1140
FIX::Tags::MinCabPrice	Messaging::FIX::Tags::MinCabPrice	9850
FIX::Tags::MinLotSize	Messaging::FIX::Tags::MinLotSize	1231
FIX::Tags::MinPriceIncrement	Messaging::FIX::Tags::MinPriceIncrement	969
FIX::Tags::MinPriceIncrementAmount	Messaging::FIX::Tags::MinPriceIncrementAmount	1146
FIX::Tags::MinQuoteLife	Messaging::FIX::Tags::MinQuoteLife	37731
FIX::Tags::MinTradeVol	Messaging::FIX::Tags::MinTradeVol	562
FIX::Tags::NoChunks	Messaging::FIX::Tags::Chunks	37709
FIX::Tags::NoEvents	Messaging::FIX::Tags::Events	864
FIX::Tags::NoInstAttrib	Messaging::FIX::Tags::InstAttrib	870
FIX::Tags::NoLegs	Messaging::FIX::Tags::Legs	555
FIX::Tags::NoLotTypeRules	Messaging::FIX::Tags::LotTypeRules	1234
FIX::Tags::NoMDEntries	Messaging::FIX::Tags::Entries	268
FIX::Tags::NoMDFeedTypes	Messaging::FIX::Tags::FeedTypes	1141
FIX::Tags::NoOrderIDEntries	Messaging::FIX::Tags::OrderIdEntries	37705
FIX::Tags::NoRelatedInstruments	Messaging::FIX::Tags::RelatedInstruments	1647
FIX::Tags::NoRelatedSym	Messaging::FIX::Tags::RelatedSym	146
FIX::Tags::NoTradingSessions	Messaging::FIX::Tags::TradingSessions	386
FIX::Tags::NoUnderlyings	Messaging::FIX::Tags::Underlyings	711
FIX::Tags::NumberOfOrders	Messaging::FIX::Tags::NumberOfOrders	346
FIX::Tags::OpenCloseSettlFlag	Messaging::FIX::Tags::OpenCloseSettlFlag	286
FIX::Tags::OpenInterestQty	Messaging::FIX::Tags::OpenInterestQty	5792
FIX::Tags::OrderID	Messaging::FIX::Tags::OrderId	37
FIX::Tags::OrderQty	Messaging::FIX::Tags::OrderQty	38
FIX::Tags::OrderUpdateAction	Messaging::FIX::Tags::OrderUpdateAction	37708
FIX::Tags::OriginalContractSize	Messaging::FIX::Tags::OriginalContractSize	5849
FIX::Tags::ParValue	Messaging::FIX::Tags::ParValue	37723
FIX::Tags::PartyRoleClearingOrg	Messaging::FIX::Tags::PartyRoleClearingOrg	9736
FIX::Tags::PriceDisplayFormat	Messaging::FIX::Tags::PriceDisplayFormat	9800
FIX::Tags::PricePrecision	Messaging::FIX::Tags::PricePrecision	2349
FIX::Tags::PriceQuoteCurrency	Messaging::FIX::Tags::PriceQuoteCurrency	1524
FIX::Tags::PriceQuoteMethod	Messaging::FIX::Tags::PriceQuoteMethod	1196
FIX::Tags::PriceRatio	Messaging::FIX::Tags::PriceRatio	5770
FIX::Tags::PutOrCall	Messaging::FIX::Tags::PutOrCall	201
FIX::Tags::QuoteReqID	Messaging::FIX::Tags::QuoteReqId	131
FIX::Tags::QuoteType	Messaging::FIX::Tags::QuoteType	537
FIX::Tags::RateSource	Messaging::FIX::Tags::RateSource	1446
FIX::Tags::ReferenceID	Messaging::FIX::Tags::ReferenceId	9633
FIX::Tags::RelatedSecurityID	Messaging::FIX::Tags::RelatedSecurityId	1650
FIX::Tags::RelatedSecurityIDSource	Messaging::FIX::Tags::RelatedSecurityIdSource	1651
FIX::Tags::RelatedSymbol	Messaging::FIX::Tags::RelatedSymbol	1649
FIX::Tags::RiskSet	Messaging::FIX::Tags::RiskSet	37721
FIX::Tags::RptSeq	Messaging::FIX::Tags::RptSeq	83
FIX::Tags::SecurityAltID	Messaging::FIX::Tags::SecurityAltId	455
FIX::Tags::SecurityAltIDSource	Messaging::FIX::Tags::SecurityAltIdSource	456
FIX::Tags::SecurityExchange	Messaging::FIX::Tags::SecurityExchange	207
FIX::Tags::SecurityGroup	Messaging::FIX::Tags::SecurityGroup	1151
FIX::Tags::SecurityID	Messaging::FIX::Tags::SecurityId	48
FIX::Tags::SecurityIDSource	Messaging::FIX::Tags::SecurityIdSource	22
FIX::Tags::SecuritySubType	Messaging::FIX::Tags::SecuritySubType	762
FIX::Tags::SecurityTradingEvent	Messaging::FIX::Tags::SecurityTradingEvent	1174
FIX::Tags::SecurityTradingStatus	Messaging::FIX::Tags::SecurityTradingStatus	326
FIX::Tags::SecurityType	Messaging::FIX::Tags::SecurityType	167
FIX::Tags::SecurityUpdateAction	Messaging::FIX::Tags::SecurityUpdateAction	980
FIX::Tags::SettlCurrency	Messaging::FIX::Tags::SettlCurrency	120
FIX::Tags::SettlDate	Messaging::FIX::Tags::SettlDate	64
FIX::Tags::SettlPriceType	Messaging::FIX::Tags::SettlPriceType	731
FIX::Tags::SettlType	Messaging::FIX::Tags::SettlType	63
FIX::Tags::SettlementLocale	Messaging::FIX::Tags::SettlementLocale	37734
FIX::Tags::Side	Messaging::FIX::Tags::Side	54
FIX::Tags::StrikeCurrency	Messaging::FIX::Tags::StrikeCurrency	947
FIX::Tags::StrikePrice	Messaging::FIX::Tags::StrikePrice	202
FIX::Tags::SubFraction	Messaging::FIX::Tags::SubFraction	37703
FIX::Tags::Symbol	Messaging::FIX::Tags::Symbol	55
FIX::Tags::Text	Messaging::FIX::Tags::Text	58
FIX::Tags::TickRule	Messaging::FIX::Tags::TickRule	6350
FIX::Tags::TotNumReports	Messaging::FIX::Tags::TotNumReports	911
FIX::Tags::TradeDate	Messaging::FIX::Tags::TradeDate	75
FIX::Tags::TradeableSize	Messaging::FIX::Tags::TradeableSize	37719
FIX::Tags::TradingReferenceDate	Messaging::FIX::Tags::TradingReferenceDate	5796
FIX::Tags::TradingReferencePrice	Messaging::FIX::Tags::TradingReferencePrice	1150
FIX::Tags::TransactTime	Messaging::FIX::Tags::TransactTime	60
FIX::Tags::UnderlyingProduct	Messaging::FIX::Tags::UnderlyingProduct	462
FIX::Tags::UnderlyingSecurityID	Messaging::FIX::Tags::UnderlyingSecurityId	309
FIX::Tags::UnderlyingSecurityIDSource	Messaging::FIX::Tags::UnderlyingSecurityIdSource	305
FIX::Tags::UnderlyingSymbol	Messaging::FIX::Tags::UnderlyingSymbol	311
FIX::Tags::UnitOfMeasure	Messaging::FIX::Tags::UnitOfMeasure	996
FIX::Tags::UnitOfMeasureQty	Messaging::FIX::Tags::UnitOfMeasureQty	1147
FIX::Tags::UserDefinedInstrument	Messaging::FIX::Tags::UserDefinedInstrument	9779

Non-Mechanical Changes

These changes are not just a namespace prefix and deserve source review.

Field Conversion

Field::cast<T>() still exists for throwing conversions. The old generic non-throwing tryCast(...) style was replaced by named non-throwing methods.

Old use	New method
convert to StrRef	toStringRef(value)
convert to Char	toChar(value)
convert to integer or decimal	toNumber(value)
convert to timestamp	toTimestamp(value)
convert to maturity month-year	toMaturityMonthYear(value)
convert to enum	toEnumeration<EnumType>(value)
convert to bitset	toBitSet(value)

Before:

using namespace OnixS::CME::MDH;
using namespace OnixS::CME::MDH::FIX;
 
Int32 size;
if (entry[Tags::MDEntrySize].tryCast(size))
{
    // use size
}

After:

namespace Msg = OnixS::CME::MDH::Messaging;
namespace FIX = OnixS::CME::MDH::Messaging::FIX;
 
Msg::Int32 size;
if (entry[FIX::Tags::EntrySize].toNumber(size))
{
    // use size
}

Enum conversion also names the enum type explicitly:

Msg::SecurityUpdateAction::Enum action;
if (message.field(FIX::Tags::SecurityUpdateAction)
        .toEnumeration<Msg::SecurityUpdateAction>(action))
{
    // use action
}

String References

StrRef moved to Messaging::StrRef. In C++17 builds, Messaging::StrRef is an alias for std::basic_string_view<Messaging::Char>. In older language modes, it remains a lightweight string-reference class with a string-view-like API.

The old StrRef::items() member is compatibility-only. Use data() or begin().

Before:

StrRef ref = security.symbol();
std::string value(ref.items(), ref.size());
stream.write(ref.items(), ref.size());

After:

Messaging::StrRef ref = security.symbol();
std::string value(ref.data(), ref.size());
stream.write(ref.data(), ref.size());

Listener Signatures

Most public listener callback argument aliases remain in OnixS::CME::MDH, but their wrapped message types moved into Messaging.

Old pattern	New pattern
BinaryMessage message = args.message();	Messaging::SbeMessage message = args.message();
FIX::MultiContainerArgs	MultiContainerArgs
FIX::MultiContainer	Messaging::FIX::MultiContainer
SnapshotFullRefresh69Args	SnapshotFullRefreshLongQty69Args
primitive aliases in callback signatures, such as UInt32 or Char	Messaging::UInt32, Messaging::Char

Before:

void onRecovery(Handler&, const Security&, const SnapshotFullRefresh69Args&) override;
 
void onMessage(Handler&, const FIX::MultiContainerArgs& args) override
{
    const auto definition = args.message();
}

After:

void onRecovery(Handler&, const Security&, const SnapshotFullRefreshLongQty69Args&) override;
 
void onMessage(Handler&, const MultiContainerArgs& args) override
{
    const auto definition = args.message();
}

SecurityListener Signatures

SecurityListener remains in OnixS::CME::MDH. Its callback argument aliases also remain in OnixS::CME::MDH, but those aliases now wrap Messaging::* message types. This matters most for exact override signatures and for code that names the message or entry type returned from an argument object.

Common SecurityListener aliases to check include:

• MultiContainerArgs
• SecurityStatus30Args
• TradeSummary48Args and TradeSummary65Args
• Recovery52EntryArgs, Recovery69EntryArgs, and MboRecovery53EntryArgs
• SnapshotFullRefresh52Args, SnapshotFullRefreshLongQty69Args, and SnapshotFullRefreshOrderBook53Args
• MbpBook46AtomicUpdateArgs, MbpBook64AtomicUpdateArgs, and the MBO book atomic update aliases

Before:

struct Listener : SecurityListener
{
    void onRecovery(Handler&, const Security&, const SnapshotFullRefresh69Args&) override;
    void onGap(Handler&, const Security&, UInt32) override;
};

After:

struct Listener : SecurityListener
{
    void onRecovery(Handler&, const Security&, const SnapshotFullRefreshLongQty69Args&) override;
    void onGap(Handler&, const Security&, Messaging::UInt32) override;
};

If an implementation inspects the wrapped message, qualify that message with Messaging:::

void onTrade(Handler&, const Security&, const TradeSummary48Args& args) override
{
    const auto message = args.message();
    const auto entry = args.entry();
}

Accessor Helpers

FIX accessor helpers moved out of the old FIX namespace and now accept Messaging::FIX::MultiContainer.

Before:

FIX::MultiContainer definition = args.message();
 
SecurityId id = FIX::securityId(definition);
StrRef group = FIX::securityGroup(definition);
Timestamp lastUpdate = FIX::timestamp(definition, FIX::Tags::LastUpdateTime);

After:

Messaging::FIX::MultiContainer definition = args.message();
 
SecurityId id = securityId(definition);
Messaging::StrRef group = securityGroup(definition);
Messaging::Timestamp lastUpdate =
    timestamp(definition, Messaging::FIX::Tags::LastUpdateTime);

SBE Messages in Packets

BinaryMessage was replaced by Messaging::SbeMessage. BinaryMessageIterator and BinaryMessages still exist in OnixS::CME::MDH, but dereferencing the iterator now returns Messaging::SbeMessage.

for (Messaging::SbeMessage message : packet.messages())
{
    // inspect message
}
 
Messaging::Timestamp sendingTime = packet.sendingTime();
Messaging::Timestamp receiveTime = netPacket.receiveTime();

SBE Group Types

The old SBE group helper names from BinaryMessage.h are deprecated compatibility aliases. Use the Sbe* names under Messaging when manually inspecting SBE repeating groups:

Old group helper	New group helper
BinaryGroupEntry<Length>	Messaging::SbeGroupEntry<Length>
BinaryGroupEntries<EntryType, Length, NumInGroup, EncodedLength>	Messaging::SbeGroupEntries<EntryType, Length, NumInGroup, EncodedLength>
BinaryGroup<EntryType, DimensionType, LengthType>	Messaging::SbeGroup<EntryType, DimensionType, LengthType>
BinaryGroups<Length>	Messaging::SbeGroupList<Length>

End-to-End Example

Before:

#include <OnixS/CME/MDH.h>
 
using namespace OnixS::CME::MDH;
 
class Listener : public MarketDataListener
{
    void onMessage(Handler&, const IncrementalRefreshBook46Args& args) override
    {
        const auto message = args.message();
        const auto indicator = message.matchEventIndicator();
        const auto text = toStr(indicator);
    }
};
 
void inspect(const FIX::Message& message)
{
    using namespace OnixS::CME::MDH::FIX;
 
    const Group entries = message.group(Tags::NoMDEntries);
    if (entries)
    {
        const auto entry = entries[0];
 
        Int32 size;
        if (entry[Tags::MDEntrySize].tryCast(size))
        {
            std::cout << size << std::endl;
        }
    }
}

After:

#include <OnixS/CME/MDH.h>
 
using namespace OnixS::CME::MDH;
 
namespace Msg = OnixS::CME::MDH::Messaging;
namespace FIX = OnixS::CME::MDH::Messaging::FIX;
 
class Listener : public MarketDataListener
{
    void onMessage(Handler&, const IncrementalRefreshBook46Args& args) override
    {
        const auto message = args.message();
        const auto indicator = message.matchEventIndicator();
        const auto text = Msg::toStr(indicator);
    }
};
 
void inspect(const FIX::Message& message)
{
    const auto entries = message.group(FIX::Tags::Entries);
    if (entries)
    {
        const auto entry = entries[0];
 
        Msg::Int32 size;
        if (entry[FIX::Tags::EntrySize].toNumber(size))
        {
            std::cout << size << std::endl;
        }
    }
}

Common Hard-Cutover Errors

Most projects should see warnings before errors. Hard errors for the messaging API usually appear only when ONIXS_CMEMDH_MESSAGING_NO_DEPRECATED is defined, when old headers are removed from include paths, or when code touches an API that was actually renamed or removed. Deprecated non-messaging API members are excluded separately by ONIXS_CMEMDH_NO_DEPRECATED, for example in handler, settings, replay, and logging headers.

Error	Fix
old header deprecation warning	Replace the include using the header table.
‘'Timestamp’ was not declared in this scope \ilinebr </td> <td class="markdownTableBodyNone"> Use Messaging::Timestamp or a namespace alias such as Msg::Timestamp. \ilinebr </td> </tr> <tr class="markdownTableRowOdd"> <td class="markdownTableBodyNone"> 'FIX' is not a namespace-name \ilinebr </td> <td class="markdownTableBodyNone"> Use namespace FIX = OnixS::CME::MDH::Messaging::FIX;. \ilinebr </td> </tr> <tr class="markdownTableRowEven"> <td class="markdownTableBodyNone"> class StrRef has no member named items \ilinebr </td> <td class="markdownTableBodyNone"> Use ref.data() or ref.begin(). \ilinebr </td> </tr> <tr class="markdownTableRowOdd"> <td class="markdownTableBodyNone"> marked override, but does not override \ilinebr </td> <td class="markdownTableBodyNone"> Check listener aliases and primitive types in the signature. \ilinebr </td> </tr> <tr class="markdownTableRowEven"> <td class="markdownTableBodyNone"> tryCast is not a member of Messaging::FIX::Field \ilinebr </td> <td class="markdownTableBodyNone"> Use the named non-throwing conversion methods. \ilinebr </td> </tr> <tr class="markdownTableRowOdd"> <td class="markdownTableBodyNone"> Tags::MDEntryPx or Tags::NoMDEntries` is not found	Use the normalized tag names from the tag table.

Most business logic should remain unchanged after these API updates are complete.