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, record_view const & rec);

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.
`rec`	A log record view. The attribute value will be sought among those associated with the record.

Returns:

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