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

Function template extract

boost::log::extract

Synopsis

// In header: <boost/log/attributes/value_extraction.hpp>


template<typename T, typename TagT = void> 
  result_of::extract< T, TagT >::type 
  extract(attribute_name const & name, attribute_value_set const & attrs);

Description

The function extracts an attribute value from the view. The user has to explicitly specify the type or set of possible types of the attribute value to be extracted.

Parameters:

`name`	The name of the attribute value to extract.
`attrs`	A set of attribute values in which to look for the specified attribute value.

Returns:

A value_ref that refers to the extracted value, if found. An empty value otherwise.