Function Template `compose`

Description
Headers
Reference

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

namespace boost { namespace iostreams {

template<typename Filter, typename FilterOrDevice>
class composite {
public:
    typedef typename char_type_of<Filter>::type  char_type;
    typedef implementation-defined               mode;

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

    // Filter or Device member functions
};

template<typename Filter, typename FilterOrDevice>
composite<Filter, FilterOrDevice> 
compose(const Filter& first, [const] FilterOrDevice& second);

} } // End namespace boost::io

Class Template `composite`

Template parameters

Filter	-	A model of Filter
FilterOrDevice	-	A model of Filter or Device

`composite::composite`

    composite(const Filter& 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.