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The slog class is used to stream messages to the system's logging facility (syslogd).
A default slog
object is used to avoid confusion with the native syslog
facility and to imply a logical relationship to the C++ clog()
.
The key difference is that the slog
object sends it's output to the
system logging daemon (typically syslogd) rather than through stderr.
slog
can be streamed with the <<
operator just
like clog
; a default slog object is pre-initialized, and you stream
character data to it.
The slog
allows one to specify logging levels and other properties through the ()
operators.
Hence, once can do:
slog("mydaemon", SLOG_DAEMON, SLOG_EMERGENCY) << I just died << endl;
or things like:
slog("mydaemon", SLOG_DAEMON);
slog(SLOG_INFO) << "daemon initalized" << endl;
The intent is to be as common-place and as convenient to use as the stderr based clog facility found in C++, and this is especially useful for C++ daemons.
The std::flush
manipulator doesn't work. Either the
std::endl
or std::ends
manipulators
must be used to cause the output to be sent to the daemon.
When this class is used on a system that doesn't have the syslog headers (i.e. a non-posix win32 box), the output goes to the a file with the same name as the syslog identifier string with '.log' appended to it. If the identifier string ends in '.exe', the '.exe' is removed before the '.log' is appened. (e.g. the identifier foo.exe will generate a log file named foo.log)
int overflow (int c)
| overflow |
[protected]
This is the streambuf function that actually outputs the data to the device. Since all output should be done with the standard ostream operators, this function should never be called directly.
Slog (void)
| Slog |
Default (and only) constructor. The default log level is set to
SLOG_DEBUG. There is no default log facility set. One should be
set before attempting any output. This is done by the open()
or the
operator()(const char*, slog_class_t, slog_level_t)
functions.
~Slog (void)
| ~Slog |
[virtual]
void close (void)
| close |
void open (const char *ident, slog_class_t grp = SLOG_USER)
| open |
(re)opens the output stream.
Parameters:
ident | The identifier portion of the message sent to the syslog daemon. |
grp | The log facility the message is sent to |
Slog & operator() (const char *ident, slog_class_t grp = SLOG_USER,
slog_level_t level = SLOG_ERROR)
| operator() |
Sets the log identifier, level, and class to use for subsequent output
Parameters:
ident | The identifier portion of the message |
grp | The log facility the message is sent to |
level | The log level of the message |
Slog & operator() (slog_level_t level, slog_class_t = SLOG_DEFAULT)
| operator() |
Changes the log level and class to use for subsequent output
Parameters:
level | The log level of the message |
grp | The log facility the message is sent to |
Slog & operator() (void)
| operator() |
Does nothing except return *this.
inline void level (slog_level_t enable)
| level |
Sets the logging level.
Parameters:
enable | is the logging level to use for further output |
inline void clogEnable (bool f=true)
| clogEnable |
Enables or disables the echoing of the messages to clog in addition to the syslog daemon. This is enabled by the default class constructor.
Parameters:
f | true to enable, false to disable clog output |