1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
|
/*
* 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;
}
|
