Type Code Support
[Topic Module]

<<eXtension>> A DDS::TypeCode is a mechanism for representing a type at runtime. RTI Data Distribution Service can use type codes to send type definitions on the network. You will need to understand this API in order to use the Dynamic Data capability or to inspect the type information you receive from remote readers and writers. More...

Classes
class	DDS::TypeCode
	The definition of a particular data type, which you can use to inspect the name, members, and other properties of types generated with rtiddsgen or to modify types you define yourself at runtime. More...
class	DDS::StructMember
	A description of a member of a struct. More...
class	DDS::StructMemberSeq
	Defines a sequence of struct members. More...
class	DDS::UnionMember
	A description of a member of a union. More...
class	DDS::UnionMemberSeq
	Defines a sequence of union members. More...
class	DDS::EnumMember
	A description of a member of an enumeration. More...
class	DDS::EnumMemberSeq
	Defines a sequence of enumerator members. More...
class	DDS::ValueMember
	A description of a member of a value type. More...
class	DDS::ValueMemberSeq
	Defines a sequence of value members. More...
class	DDS::TypeCodeFactory
	A singleton factory for creating, copying, and deleting data type definitions dynamically. More...
Enumerations
enum	DDS::TCKind {   DDS::TK_NULL,   DDS::TK_SHORT,   DDS::TK_LONG,   DDS::TK_USHORT,   DDS::TK_ULONG,   DDS::TK_FLOAT,   DDS::TK_DOUBLE,   DDS::TK_BOOLEAN,   DDS::TK_CHAR,   DDS::TK_OCTET,   DDS::TK_STRUCT,   DDS::TK_UNION,   DDS::TK_ENUM,   DDS::TK_STRING,   DDS::TK_SEQUENCE,   DDS::TK_ARRAY,   DDS::TK_ALIAS,   DDS::TK_LONGLONG,   DDS::TK_ULONGLONG,   DDS::TK_LONGDOUBLE,   DDS::TK_WCHAR,   DDS::TK_WSTRING,   DDS::TK_VALUE,   DDS::TK_SPARSE }
	Enumeration type for DDS::TypeCode kinds. More...
enum	DDS::ValueModifier {   DDS::VM_NONE,   DDS::VM_CUSTOM,   DDS::VM_ABSTRACT,   DDS::VM_TRUNCATABLE }
	Modifier type for a value type. More...
enum	DDS::Visibility {   DDS::PRIVATE_MEMBER,   DDS::PUBLIC_MEMBER }
	Type to indicate the visibility of a value type member. More...
Variables
TypeCode^	DDS::TypeCode::TC_NULL
	Basic null type.
TypeCode^	DDS::TypeCode::TC_LONG
	Basic 32-bit signed integer type.
TypeCode^	DDS::TypeCode::TC_USHORT
	Basic unsigned 16-bit integer type.
TypeCode^	DDS::TypeCode::TC_ULONG
	Basic unsigned 32-bit integer type.
TypeCode^	DDS::TypeCode::TC_FLOAT
	Basic 32-bit floating point type.
TypeCode^	DDS::TypeCode::TC_DOUBLE
	Basic 64-bit floating point type.
TypeCode^	DDS::TypeCode::TC_BOOLEAN
	Basic Boolean type.
TypeCode^	DDS::TypeCode::TC_OCTET
	Basic octet/byte type.
TypeCode^	DDS::TypeCode::TC_LONGLONG
	Basic 64-bit integer type.
TypeCode^	DDS::TypeCode::TC_ULONGLONG
	Basic unsigned 64-bit integer type.
TypeCode^	DDS::TypeCode::TC_LONGDOUBLE
	Basic 128-bit floating point type.
TypeCode^	DDS::TypeCode::TC_WCHAR
	Basic four-byte character type.
System::Int32	DDS::TypeCode::MEMBER_ID_INVALID
	A sentinel indicating an invalid DDS::TypeCode member ID.
System::UInt32	DDS::TypeCode::INDEX_INVALID
	A sentinel indicating an invalid DDS::TypeCode member index.
System::Int16	DDS::TypeCode::NOT_BITFIELD
	Indicates that a member of a type is not a bitfield.
System::Byte	DDS::TypeCode::NONKEY_MEMBER
	A flag indicating that a type member is optional and not part of the key.
System::Byte	DDS::TypeCode::KEY_MEMBER
	A flag indicating that a type member is part of the key for that type, and therefore required.
System::Byte	DDS::TypeCode::NONKEY_REQUIRED_MEMBER
	A flag indicating that a type member is not part of the key but is nevertheless required.

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Detailed Description

<<eXtension>> A DDS::TypeCode is a mechanism for representing a type at runtime. RTI Data Distribution Service can use type codes to send type definitions on the network. You will need to understand this API in order to use the Dynamic Data capability or to inspect the type information you receive from remote readers and writers.

Type codes are values that are used to describe arbitrarily complex types at runtime. Type code values are manipulated via the DDS::TypeCode class, which has an analogue in CORBA.

A DDS::TypeCode value consists of a type code kind (represented by the DDS::TCKind enumeration) and a list of members (that is, fields). These members are recursive: each one has its own DDS::TypeCode, and in the case of complex types (structures, arrays, and so on), these contained type codes contain their own members.

There are a number of uses for type codes. The type code mechanism can be used to unambiguously match type representations. The DDS::TypeCode::Equals method is a more reliable test than comparing the string type names, requiring equivalent definitions of the types.

Accessing a Local ::DDS::TypeCode

When generating types with rtiddsgen, type codes are enabled by default. (The -notypecode option can be used to disable generation of DDS::TypeCode information.) For these types, a DDS::TypeCode may be accessed via the FooTypeCode.VALUE member.

This API also includes support for dynamic creation of DDS::TypeCode values, typically for use with the Dynamic Data API. You can create a DDS::TypeCode using the DDS::TypeCodeFactory class. You will construct the DDS::TypeCode recursively, from the outside in: start with the type codes for primitive types, then compose them into complex types like arrays, structures, and so on. You will find the following methods helpful:

• DDS::TypeCodeFactory::get_primitive_tc, which provides the DDS::TypeCode instances corresponding to the primitive types (e.g. DDS::TCKind::TK_LONG, DDS::TCKind::TK_SHORT, and so on).
• DDS::TypeCodeFactory::create_string_tc and DDS::TypeCodeFactory::create_wstring_tc create a DDS::TypeCode representing a text string with a certain bound (i.e. maximum length).
• DDS::TypeCodeFactory::create_array_tc and DDS::TypeCodeFactory::create_sequence_tc create a DDS::TypeCode for a collection based on the DDS::TypeCode for its elements.
• DDS::TypeCodeFactory::create_struct_tc, DDS::TypeCodeFactory::create_value_tc, and DDS::TypeCodeFactory::create_sparse_tc create a DDS::TypeCode for a structured type.

Accessing a Remote ::DDS::TypeCode

In addition to being used locally, RTI Data Distribution Service can transmit DDS::TypeCode on the network between participants. This information can be used to access information about types used remotely at runtime, for example to be able to publish or subscribe to topics of arbitrarily types (see Dynamic Data). This functionality is useful for a generic system monitoring tool like rtiddsspy.

Remote DDS::TypeCode information is shared during discovery over the publication and subscription built-in topics and can be accessed using the built-in readers for these topics; see Built-in Topics. Discovered DDS::TypeCode values are not cached by RTI Data Distribution Service upon receipt and are therefore not available from the built-in topic data returned by DDS::DataWriter::get_matched_subscription_data or DDS::DataReader::get_matched_publication_data.

The space available locally to deserialize a discovered remote DDS::TypeCode is specified by the DDS::DomainParticipant's DDS::DomainParticipantResourceLimitsQosPolicy::type_code_max_serialized_length QoS parameter. To support especially complex type codes, it may be necessary for you to increase the value of this parameter.

See also:

DDS::TypeCode

Dynamic Data

rtiddsgen

DDS::SubscriptionBuiltinTopicData

DDS::PublicationBuiltinTopicData

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Enumeration Type Documentation

enum DDS::TCKind

Enumeration type for DDS::TypeCode kinds.

Type code kinds are modeled as values of this type.

Enumerator:

TK_NULL	Indicates that a type code does not describe anything.
TK_SHORT	short type.
TK_LONG	long type.
TK_USHORT	unsigned short type.
TK_ULONG	unsigned long type.
TK_FLOAT	float type.
TK_DOUBLE	double type.
TK_BOOLEAN	boolean type.
TK_CHAR	char type.
TK_OCTET	octet type.
TK_STRUCT	struct type.
TK_UNION	union type.
TK_ENUM	enumerated type.
TK_STRING	string type.
TK_SEQUENCE	sequence type.
TK_ARRAY	array type.
TK_ALIAS	alias (typedef) type.
TK_LONGLONG	long long type.
TK_ULONGLONG	unsigned long long type.
TK_LONGDOUBLE	long double type.
TK_WCHAR	wide char type.
TK_WSTRING	wide string type.
TK_VALUE	value type.
TK_SPARSE	A sparse value type. A sparse value type is one in which all of the fields are not necessarily sent on the network as a part of every sample. Fields of a sparse value type fall into one of three categories: Key fields (see DDS::TypeCode::KEY_MEMBER) Non-key, but required members (see DDS::TypeCode::NONKEY_REQUIRED_MEMBER) Non-key, optional members (see DDS::TypeCode::NONKEY_MEMBER) Fields of the first two kinds must appear in every sample. These are also the only kinds of fields on which you can perform content filtering (see DDS::ContentFilteredTopic), because filter evaluation on a non-existent field is not well defined.

enum DDS::ValueModifier

Modifier type for a value type.

See also:

DDS::ValueModifier::VM_NONE

DDS::ValueModifier::VM_CUSTOM

DDS::ValueModifier::VM_ABSTRACT

DDS::ValueModifier::VM_TRUNCATABLE

Enumerator:

VM_NONE	Constant used to indicate that a value type has no modifiers. See also: DDS::ValueModifier
VM_CUSTOM	Constant used to indicate that a value type has the custom modifier. This modifier is used to specify whether the value type uses custom marshaling. See also: DDS::ValueModifier
VM_ABSTRACT	Constant used to indicate that a value type has the abstract modifier. An abstract value type may not be instantiated. See also: DDS::ValueModifier
VM_TRUNCATABLE	Constant used to indicate that a value type has the truncatable modifier. A value with a state that derives from another value with a state can be declared as truncatable. A truncatable type means the object can be truncated to the base type. See also: DDS::ValueModifier

enum DDS::Visibility

Type to indicate the visibility of a value type member.

See also:

DDS::Visibility::PRIVATE_MEMBER

DDS::Visibility::PUBLIC_MEMBER

Enumerator:

PRIVATE_MEMBER	Constant used to indicate that a value type member is private. See also: DDS::Visibility DDS::Visibility::PUBLIC_MEMBER
PUBLIC_MEMBER	Constant used to indicate that a value type member is public. See also: DDS::Visibility DDS::Visibility::PRIVATE_MEMBER

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Variable Documentation

TypeCode ^ DDS::TypeCode::TC_NULL [inherited]

Basic null type.

See also:

DDS::TypeCodeFactory::get_primitive_tc

TypeCode ^ DDS::TypeCode::TC_LONG [inherited]

Basic 32-bit signed integer type.

See also:

DDS::TypeCodeFactory::get_primitive_tc

TypeCode ^ DDS::TypeCode::TC_USHORT [inherited]

Basic unsigned 16-bit integer type.

See also:

DDS::TypeCodeFactory::get_primitive_tc

TypeCode ^ DDS::TypeCode::TC_ULONG [inherited]

Basic unsigned 32-bit integer type.

See also:

DDS::TypeCodeFactory::get_primitive_tc

TypeCode ^ DDS::TypeCode::TC_FLOAT [inherited]

Basic 32-bit floating point type.

See also:

DDS::TypeCodeFactory::get_primitive_tc

TypeCode ^ DDS::TypeCode::TC_DOUBLE [inherited]

Basic 64-bit floating point type.

See also:

DDS::TypeCodeFactory::get_primitive_tc

TypeCode ^ DDS::TypeCode::TC_BOOLEAN [inherited]

Basic Boolean type.

See also:

DDS::TypeCodeFactory::get_primitive_tc

TypeCode ^ DDS::TypeCode::TC_OCTET [inherited]

Basic octet/byte type.

See also:

DDS::TypeCodeFactory::get_primitive_tc

TypeCode ^ DDS::TypeCode::TC_LONGLONG [inherited]

Basic 64-bit integer type.

See also:

DDS::TypeCodeFactory::get_primitive_tc

TypeCode ^ DDS::TypeCode::TC_ULONGLONG [inherited]

Basic unsigned 64-bit integer type.

See also:

DDS::TypeCodeFactory::get_primitive_tc

TypeCode ^ DDS::TypeCode::TC_LONGDOUBLE [inherited]

Basic 128-bit floating point type.

See also:

DDS::TypeCodeFactory::get_primitive_tc

TypeCode ^ DDS::TypeCode::TC_WCHAR [inherited]

Basic four-byte character type.

See also:

DDS::TypeCodeFactory::get_primitive_tc

System::Int32 DDS::TypeCode::MEMBER_ID_INVALID [inherited]

A sentinel indicating an invalid DDS::TypeCode member ID.

System::UInt32 DDS::TypeCode::INDEX_INVALID [inherited]

A sentinel indicating an invalid DDS::TypeCode member index.

System::Int16 DDS::TypeCode::NOT_BITFIELD [inherited]

Indicates that a member of a type is not a bitfield.

System::Byte DDS::TypeCode::NONKEY_MEMBER [inherited]

A flag indicating that a type member is optional and not part of the key.

Only sparse value types (i.e. types of DDS::TCKind DDS::TCKind::TK_SPARSE) support this flag. Non-key members of other type kinds should use the flag DDS::TypeCode::NONKEY_REQUIRED_MEMBER.

If a type is used with the Dynamic Data facility, a DDS::DynamicData sample of the type will only contain a value for a DDS::TypeCode::NONKEY_MEMBER field if one has been explicitly set (see, for example, DDS::DynamicData::set_int). The middleware will not assume any default value.

See also:

DDS::TypeCode::KEY_MEMBER

DDS::TypeCode::NONKEY_REQUIRED_MEMBER

DDS::TypeCode::KEY_MEMBER

DDS::TypeCode::add_member

DDS::TypeCode::add_member_ex

DDS::TypeCode::is_member_key

DDS::TypeCode::is_member_required

DDS::StructMember::is_key

DDS::ValueMember::is_key

System::Byte DDS::TypeCode::KEY_MEMBER [inherited]

A flag indicating that a type member is part of the key for that type, and therefore required.

If a type is used with the Dynamic Data facility, all DDS::DynamicData samples of the type will contain a value for all DDS::TypeCode::KEY_MEMBER fields, even if the type is a sparse value type (i.e. of kind DDS::TCKind::TK_SPARSE). If you do not set a value of the member explicitly (see, for example, DDS::DynamicData::set_int), the middleware will assume a default "zero" value: numeric values will be set to zero; strings and sequences will be of zero length.

See also:

DDS::TypeCode::NONKEY_REQUIRED_MEMBER

DDS::TypeCode::NONKEY_MEMBER

DDS::TypeCode::add_member

DDS::TypeCode::add_member_ex

DDS::TypeCode::is_member_key

DDS::TypeCode::is_member_required

DDS::StructMember::is_key

DDS::ValueMember::is_key

System::Byte DDS::TypeCode::NONKEY_REQUIRED_MEMBER [inherited]

A flag indicating that a type member is not part of the key but is nevertheless required.

This is the most common kind of member.

If a type is used with the Dynamic Data facility, all DDS::DynamicData samples of the type will contain a value for all DDS::TypeCode::NONKEY_REQUIRED_MEMBER fields, even if the type is a sparse value type (i.e. of kind DDS::TCKind::TK_SPARSE). If you do not set a value of the member explicitly (see, for example, DDS::DynamicData::set_int), the middleware will assume a default "zero" value: numeric values will be set to zero; strings and sequences will be of zero length.

See also:

DDS::TypeCode::KEY_MEMBER

DDS::TypeCode::NONKEY_MEMBER

DDS::TypeCode::KEY_MEMBER

DDS::TypeCode::add_member

DDS::TypeCode::add_member_ex

DDS::TypeCode::is_member_key

DDS::TypeCode::is_member_required

DDS::StructMember::is_key

DDS::ValueMember::is_key