Function Template `compose`

Description

Given a Filter f and a Device d, we may construct a device c whose member functions are implemented by invoking the fundamental i/o operations read, write, etc. with f as the first argument and d as the second. Similarly, if we are given two filters f1 and f2, we may construct a third filter f3 whose member function templates are implemented by invoking the fundamental i/o operations read, write, etc., with first argument equal to f1 and second argument equal to the result of composing f2 with the provided Device.

The function template composite represents a Filter or Device which has been constructed in the above manner. The function template compose is an object generator which given a pair of components returns an appropriate instance of composite.

The mode of a composite is defined to provide a maximal subset of the common functionality of the two components. A composite is Closable, Flushable, Localizable and OptimallyBuffered.

Headers

<boost/iostreams/compose.hpp>

Reference

Synopsis

namespaceboost {namespaceiostreams {template<typename[Filter](#composite_template_params),typename[FilterOrDevice](#composite_template_params)>class[composite](#composite){public:typedeftypename[char\_type\_of](../guide/traits.html#char_type)<Filter>::type char_type;typedefimplementation-definedmode;[composite](#composite_ctor)(constFilter& first, [const] FilterOrDevice& second);// Filter or Device member functions};template<typename[Filter](#compose_template_params),typename[FilterOrDevice](#compose_template_params)>[composite](#composite)<Filter, FilterOrDevice>[compose](#compose)(constFilter& first, [const] FilterOrDevice& second);

} } // End namespace boost::io

Class Template `composite`

Template parameters

`composite::composite`

composite(constFilter& first, [const] FilterOrDevice& second);

Constructs an instance of composite based on the given components. If FilterOrDevice is a stream or stream buffer type, the second parameter is a non-const reference; otherwise it is a const reference.