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- /*
- * Copyright Andrey Semashev 2007 - 2015.
- * Distributed under the Boost Software License, Version 1.0.
- * (See accompanying file LICENSE_1_0.txt or copy at
- * http://www.boost.org/LICENSE_1_0.txt)
- */
- #include <cstddef>
- #include <iostream>
- #include <boost/log/core.hpp>
- #include <boost/log/expressions.hpp>
- #include <boost/log/attributes.hpp>
- #include <boost/log/utility/value_ref.hpp>
- namespace logging = boost::log;
- namespace expr = boost::log::expressions;
- namespace sinks = boost::log::sinks;
- namespace attrs = boost::log::attributes;
- namespace keywords = boost::log::keywords;
- // We define our own severity levels
- enum severity_level
- {
- normal,
- notification,
- warning,
- error,
- critical
- };
- // The operator puts a human-friendly representation of the severity level to the stream
- std::ostream& operator<< (std::ostream& strm, severity_level level)
- {
- static const char* strings[] =
- {
- "normal",
- "notification",
- "warning",
- "error",
- "critical"
- };
- if (static_cast< std::size_t >(level) < sizeof(strings) / sizeof(*strings))
- strm << strings[level];
- else
- strm << static_cast< int >(level);
- return strm;
- }
- //[ example_core_record_visitation_extraction
- //=enum severity_level { ... };
- //=std::ostream& operator<< (std::ostream& strm, severity_level level);
- struct print_visitor
- {
- typedef void result_type;
- result_type operator() (severity_level level) const
- {
- std::cout << level << std::endl;
- };
- };
- // Prints severity level through visitation API
- void print_severity_visitation(logging::record const& rec)
- {
- logging::visit< severity_level >("Severity", rec, print_visitor());
- }
- // Prints severity level through extraction API
- void print_severity_extraction(logging::record const& rec)
- {
- logging::value_ref< severity_level > level = logging::extract< severity_level >("Severity", rec);
- std::cout << level << std::endl;
- }
- //]
- //[ example_core_record_attr_value_lookup
- // Prints severity level by searching the attribute values
- void print_severity_lookup(logging::record const& rec)
- {
- logging::attribute_value_set const& values = rec.attribute_values();
- logging::attribute_value_set::const_iterator it = values.find("Severity");
- if (it != values.end())
- {
- logging::attribute_value const& value = it->second;
- // A single attribute value can also be visited or extracted
- std::cout << value.extract< severity_level >() << std::endl;
- }
- }
- //]
- //[ example_core_record_subscript
- BOOST_LOG_ATTRIBUTE_KEYWORD(severity, "Severity", severity_level)
- // Prints severity level by using the subscript operator
- void print_severity_subscript(logging::record const& rec)
- {
- // Use the attribute keyword to communicate the name and type of the value
- logging::value_ref< severity_level, tag::severity > level = rec[severity];
- std::cout << level << std::endl;
- }
- //]
- int main(int, char*[])
- {
- logging::attribute_set attrs;
- attrs.insert("Severity", attrs::make_constant(notification));
- logging::record rec = logging::core::get()->open_record(attrs);
- if (rec)
- {
- print_severity_visitation(rec);
- print_severity_extraction(rec);
- print_severity_lookup(rec);
- print_severity_subscript(rec);
- }
- return 0;
- }
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