NAME | SYNOPSIS | API RESTRICTIONS | DESCRIPTION | RETURN VALUES | EXAMPLES | ATTRIBUTES | SEE ALSO
$(OS_DIR)/lib/libc.a #include <syslog.h> #include <varargs.h>void syslog(int priority, const char *message);
The function or functions documented here may not be used safely in all application contexts with all APIs provided in the ChorusOS 5.0 product.
See API(5FEA) for details.
The syslog() function writes messages to the system message logger. The message is then written to the system console, log files, logged-in users, or forwarded to other machines as appropriate. (See syslogd(1M) ).
The message is identical to a printf(3STDC) format string, except that `%m' is replaced by the current error message, as denoted by the global variable errno (see strerror(3STDC) ). A trailing newline is added if none is present.
The vsyslog() function is an alternative form in which the arguments have already been captured using the variable-length argument facilities of varargs.
The message is tagged with a priority. Priorities are encoded as a facility and a level. The facility describes the part of the system generating the message. The level is selected from the following ordered list:
A panic condition, usually broadcast to all users.
A condition that should be corrected immediately, such as a corrupted system database.
Critical conditions, such as hard device errors.
Errors.
Warning messages.
Conditions that are not error conditions, but should possibly be paid special attention.
Informational messages.
Messages that contain information usually of use only when debugging a program.
The openlog() function allows for more specialized processing of the messages sent by syslog() and vsyslog() . The ident parameter is a string that is prepended to every message. The logopt argument is a bit field specifying logging options, which is formed by OR'ing one or more of the following values:
If syslog() cannot pass the message to syslogd() it attempts to write the message to the console ( /dev/console ).
Open the connection to syslogd() immediately. Usually, the open is delayed until the first message is logged. This is useful for programs that need to manage the order in which file descriptors are allocated.
Write the message to standard error output and to the system log.
Log the process id with each message. This is useful for identifying instantiations of daemons.
The facility parameter encodes a default facility to be assigned to all messages that do not have an explicit facility encoded:
The authorization system.
The same as LOG_AUTH, but logged to a file readable only by selected individuals.
The cron daemon.
System daemons not provided for explicitly by other facilities.
The file transfer protocol daemons.
Messages generated by the microkernel. These cannot be generated by any user processes.
The line printer spooling system.
The mail system.
The network news system.
Security subsystems.
Messages generated internally by syslogd() .
Messages generated by random user processes. This is the default facility identifier if none is specified.
The uucp system.
Reserved for local use. Similarly for LOG_LOCAL1 through LOG_LOCAL7.
The closelog() function is used to close the log file.
The setlogmask() function sets the log priority mask to maskpri and returns the previous mask. Calls to syslog() with a priority not set in maskpri are rejected. The mask for an individual priority pri is calculated by the macro LOG_MASK(pri);. The mask for all priorities up to and including toppri is given by the macro LOG_UPTO(toppri);. The default allows all priorities to be logged.
The routines syslog() , vsyslog() , openlog() , and closelog() return no value.
The routine setlogmask() always returns the previous log mask level.
syslog(LOG_ALERT, "who: internal error 23");
openlog("ftpd", LOG_PID | LOG_NDELAY, LOG_FTP);
setlogmask(LOG_UPTO(LOG_ERR));
syslog(LOG_INFO, "Connection from host %d", CallingHost);
syslog(LOG_INFO|LOG_LOCAL2, "foobar error: %m");
See attributes(5) for descriptions of the following attributes:
ATTRIBUTE TYPE | ATTRIBUTE VALUE |
---|---|
Interface Stability | Evolving |
NAME | SYNOPSIS | API RESTRICTIONS | DESCRIPTION | RETURN VALUES | EXAMPLES | ATTRIBUTES | SEE ALSO