Boost C++ Libraries

...one of the most highly regarded and expertly designed C++ library projects in the world. Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

This is the documentation for an old version of Boost. Click here to view this page for the latest version.
PrevUpHomeNext
qbegin(Predicates const &)

Returns a query iterator pointing at the begin of the query range.

Description

This method returns an iterator which may be used to perform iterative queries. For the information about predicates which may be passed to this method see query().

Synopsis
template<typename Predicates>
const_query_iterator qbegin(Predicates const & predicates)
Modifier(s)

const

Parameter(s)

Type

Name

Description

Predicates const &

predicates

Predicates.

Returns

The iterator pointing at the begin of the query range.

Example

for ( Rtree::const_query_iterator it = tree.qbegin(bgi::nearest(pt, 10000)) ;
      it != tree.qend() ; ++it )
{
    // do something with value
    if ( has_enough_nearest_values() )
        break;
}

// C++11 (auto)
for ( auto it = tree.qbegin(bgi::nearest(pt, 3)) ; it != tree.qend() ; ++it )
{
    // do something with value
}

// C++14 (generic lambda expression)
std::for_each(tree.qbegin(bgi::nearest(pt, 3)), tree.qend(), [](auto const& val){
    // do something with value
});

Iterator category

ForwardIterator

Throws

If predicates copy throws. If allocation throws.

[Warning] Warning

The modification of the rtree may invalidate the iterators.


PrevUpHomeNext