Class List
Here are the classes, structs, unions and interfaces with brief descriptions:

Xapian | The Xapian namespace contains public interfaces for the Xapian library
Error | All exceptions thrown by Xapian are subclasses of Xapian::Error
LogicError | The base class for exceptions indicating errors in the program logic
RuntimeError | The base class for exceptions indicating errors only detectable at runtime
AssertionError | AssertionError is thrown if a logical assertion inside Xapian fails
InvalidArgumentError | InvalidArgumentError indicates an invalid parameter value was passed to the API
InvalidOperationError | InvalidOperationError indicates the API was used in an invalid way
UnimplementedError | UnimplementedError indicates an attempt to use an unimplemented feature
DatabaseError | DatabaseError indicates some sort of database related error
DatabaseCorruptError | DatabaseCorruptError indicates database corruption was detected
DatabaseCreateError | DatabaseCreateError indicates a failure to create a database
DatabaseLockError | DatabaseLockError indicates failure to lock a database
DatabaseModifiedError | DatabaseModifiedError indicates a database was modified
DatabaseOpeningError | DatabaseOpeningError indicates failure to open a database
DatabaseVersionError | DatabaseVersionError indicates that a database is in an unsupported format
DocNotFoundError | Indicates an attempt to access a document not present in the database
FeatureUnavailableError | Indicates an attempt to use a feature which is unavailable
InternalError | InternalError indicates a runtime problem of some sort
NetworkError | Indicates a problem communicating with a remote database
NetworkTimeoutError | Indicates a timeout expired while communicating with a remote database
QueryParserError | Indicates a query string can't be parsed
SerialisationError | Indicates an error in the std::string serialisation of an object
RangeError | RangeError indicates an attempt to access outside the bounds of a container
WildcardError | WildcardError indicates an error expanding a wildcarded query
DatabaseNotFoundError | Indicates an attempt to access a database not present
DatabaseClosedError | Indicates an attempt to access a closed database
Compactor | Compact a database, or merge and compact several
Database | This class is used to access a database, or a group of databases
WritableDatabase | This class provides read/write access to a database
Document | A handle representing a document in a Xapian database
RSet | A relevance set (R-Set)
MatchDecider | Base class for matcher decision functor
Enquire | This class provides an interface to the information retrieval system for the purpose of searching
ErrorHandler | Decide if a Xapian::Error exception should be ignored
ESet | Class representing a list of search results
ESetIterator | Iterator over a Xapian::ESet
ExpandDecider | Virtual base class for expand decider functor
ExpandDeciderAnd | ExpandDecider subclass which rejects terms using two ExpandDeciders
ExpandDeciderFilterTerms | ExpandDecider subclass which rejects terms in a specified list
ExpandDeciderFilterPrefix | ExpandDecider subclass which restrict terms to a particular prefix
LatLongCoord | A latitude-longitude coordinate
LatLongCoordsIterator | An iterator across the values in a LatLongCoords object
LatLongCoords | A sequence of latitude-longitude coordinates
LatLongMetric | Base class for calculating distances between two lat/long coordinates
GreatCircleMetric | Calculate the great-circle distance between two coordinates on a sphere
LatLongDistancePostingSource | Posting source which returns a weight based on geospatial distance
LatLongDistanceKeyMaker | KeyMaker subclass which sorts by distance from a latitude/longitude
KeyMaker | Virtual base class for key making functors
MultiValueKeyMaker | KeyMaker subclass which combines several values
MatchSpy | Abstract base class for match spies
ValueCountMatchSpy | Class for counting the frequencies of values in the matching documents
MSet | Class representing a list of search results
MSetIterator | Iterator over a Xapian::MSet
PositionIterator | Class for iterating over term positions
PostingIterator | Class for iterating over a list of terms
PostingSource | Base class which provides an "external" source of postings
ValuePostingSource | A posting source which generates weights from a value slot
ValueWeightPostingSource | A posting source which reads weights from a value slot
DecreasingValueWeightPostingSource | Read weights from a value which is known to decrease as docid increases
ValueMapPostingSource | A posting source which looks up weights in a map using values as the key
FixedWeightPostingSource | A posting source which returns a fixed weight for all documents
Query | Class representing a query
Stopper | Base class for stop-word decision functor
SimpleStopper | Simple implementation of Stopper class - this will suit most users
RangeProcessor | Base class for range processors
DateRangeProcessor | Handle a date range
NumberRangeProcessor | Handle a number range
ValueRangeProcessor | Base class for value range processors
StringValueRangeProcessor | Handle a string range
DateValueRangeProcessor | Handle a date range
NumberValueRangeProcessor | Handle a number range
FieldProcessor | Base class for field processors
QueryParser | Build a Xapian::Query object from a user query string
Registry | Registry for user subclasses
StemImplementation | Class representing a stemming algorithm implementation
Stem | Class representing a stemming algorithm
TermGenerator | Parses a piece of text and generate terms
TermIterator | Class for iterating over a list of terms
Utf8Iterator | An iterator which returns Unicode character values from a UTF-8 encoded string
ValueIterator | Class for iterating over document values
ValueSetMatchDecider | MatchDecider filtering results based on whether document values are in a user-defined set
Weight | Abstract base class for weighting schemes
BoolWeight | Class implementing a "boolean" weighting scheme
TfIdfWeight | Xapian::Weight subclass implementing the tf-idf weighting scheme
BM25Weight | Xapian::Weight subclass implementing the BM25 probabilistic formula
BM25PlusWeight | Xapian::Weight subclass implementing the BM25+ probabilistic formula
TradWeight | Xapian::Weight subclass implementing the traditional probabilistic formula
InL2Weight | This class implements the InL2 weighting scheme
IfB2Weight | This class implements the IfB2 weighting scheme
IneB2Weight | This class implements the IneB2 weighting scheme
BB2Weight | This class implements the BB2 weighting scheme
DLHWeight | This class implements the DLH weighting scheme, which is a representative scheme of the Divergence from Randomness Framework by Gianni Amati
PL2Weight | This class implements the PL2 weighting scheme
PL2PlusWeight | Xapian::Weight subclass implementing the PL2+ probabilistic formula
DPHWeight | This class implements the DPH weighting scheme
LMWeight | Xapian::Weight subclass implementing the Language Model formula
CoordWeight | Xapian::Weight subclass implementing Coordinate Matching