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QGst::Query Class Reference

#include <QGst/Query>

Inheritance diagram for QGst::Query:
Inheritance graph
Collaboration diagram for QGst::Query:
Collaboration graph

Public Member Functions

QString typeName () const
QueryType type () const
StructureConstPtr internalStructure ()
- Public Member Functions inherited from QGst::MiniObject
MiniObjectPtr copy () const
bool isWritable () const
MiniObjectPtr makeWritable () const

Additional Inherited Members

- Public Types inherited from QGst::MiniObject
typedef GstMiniObject CType
- Protected Member Functions inherited from QGst::MiniObject
 MiniObject (const MiniObject &)
MiniObjectoperator= (const MiniObject &)
virtual void ref (bool increaseRef)
virtual void unref ()
- Protected Member Functions inherited from QGlib::RefCountedObject
template<class T >
T * object () const
- Protected Attributes inherited from QGlib::RefCountedObject
void * m_object

Detailed Description

Wrapper class for GstQuery.

Queries are lightweight objects that are sent from the application directly to elements or pads using the query() methods. A typical usage is to find out the duration or current position of media, or to display the status of a buffering operation.

Queries are implemented as a subclass of MiniObject with a generic GstStructure as the content. This allows for writing custom queries without requiring an API change while allowing a wide range of different types of queries.

QGst::Query is the common base class for all query types.

In these bindings, for convenience, each query type has its own Query subclass. The create() method in the subclasses should be used to create a query object. This does not reflect 1-1 the native C API, where there is only one Query class with tens of 'new_foo' and 'parse_foo' methods.

Note that the Query subclasses cannot be used with Value::get(), since a GValue will actually contain a GstQuery (the subclasses do not exist in C) and Value::get() is not able to do dynamic casts. As a result of that, Query subclasses also cannot be used as arguments in slots connected to GObject signals, even though you may know that your slot will only be called with that type of queries.

Definition at line 53 of file query.h.

The documentation for this class was generated from the following files: