QgsFeatureIterator class

Wrapper for iterator of features from vector data provider or vector layer.

Constructors, destructors, conversion operators

QgsFeatureIterator() defaulted: Construct invalid iterator.
QgsFeatureIterator(QgsAbstractFeatureIterator* iter): Construct a valid iterator.
QgsFeatureIterator(const QgsFeatureIterator& fi): Copy constructor copies the iterator, increases ref.count.
~QgsFeatureIterator(): Destructor deletes the iterator if it has no more references.

auto compileFailed() const -> bool: Indicator if there was an error when sending the compiled query to the server.
auto compileStatus() const -> QgsAbstractFeatureIterator::CompileStatus: Returns the status of expression compilation for filter expression requests.
auto isClosed() const -> bool: find out whether the iterator is still valid or closed already
auto isValid() const -> bool virtual: Will return if this iterator is valid.
void setInterruptionChecker(QgsFeedback* interruptionChecker): Attach an object that can be queried regularly by the iterator to check if it must stopped.

Indicator if there was an error when sending the compiled query to the server.

This indicates that there is something wrong with the expression compiler.

Returns the status of expression compilation for filter expression requests.

Will return if this iterator is valid.

An invalid iterator was probably introduced by a failed attempt to acquire a connection or is a default constructed iterator.

Attach an object that can be queried regularly by the iterator to check if it must stopped.

This is mostly useful for iterators where a single nextFeature()/fetchFeature() iteration might be very long. A typical use case is the WFS provider.