output_iterator_tag Struct

 

The latest version of this topic can be found at output_iterator_tag Struct.

A class that provides a return type for iterator_category function that represents an output iterator.

Syntax

struct output_iterator_tag {};

Remarks

The category tag classes are used as compile tags for algorithm selection. The template function needs to find the most specific category of its iterator argument so that it can use the most efficient algorithm at compile time. For every iterator of type Iterator, iterator_traits< Iterator> ::iterator_category must be defined to be the most specific category tag that describes the iterator's behavior.

The type is the same as iterator< Iter> ::iterator_category when Iter describes an object that can serve as a output iterator.

This tag is not parameterized on the value_type or difference_type for the iterator, as with the other iterator tags, because output iterators do not have either a value_type or a difference_type.

Example

See iterator_traits or random_access_iterator_tag for an example of how to use iterator_tags.

Requirements

Header: <iterator>

Namespace: std

See Also

Thread Safety in the C++ Standard Library
Standard Template Library