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BSD 2.11 - man page for openlog (bsd section 3)

SYSLOG(3)				       Library Functions Manual 				    SYSLOG(3)

syslog , vsyslog , openlog , closelog , setlogmask - control system log
#include <syslog.h> #include <varargs.h> void syslog(priority, message, ...); int priority; char *message; void vsyslog(priority, message, args); int priority; char *message; va_list args; void openlog(ident, logopt, facility); char *ident; int logopt; int facility; void closelog(); int setlogmask(maskpri); int maskpri;
The syslog() function writes message 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(8)). The message is identical to a printf(3) format string, except that %m is replaced by the current error message as denoted by the global variable errno. See strerror(3)). A trailing newline is added if none is present. The vsyslog() function is an alternate form in which the arguments have already been captured using the vari- able-length argument facilities of varargs(3). The message is tagged with 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 (high to low) list: LOG_EMERG A panic condition. This is normally broadcast to all users. LOG_ALERT A condition that should be corrected immediately, such as a corrupted system database. LOG_CRIT Critical conditions, e.g., hard device errors. LOG_ERR Errors. LOG_WARNING Warning messages. LOG_NOTICE Conditions that are not error conditions, but should possibly be handled specially. LOG_INFO Informational messages. LOG_DEBUG Messages that contain information normally of use only when debugging a program. The openlog() function provides for more specialized processing of the messages sent by syslog() and vsys- log(). The parameter ident is a string that will be 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: LOG_CONS If syslog cannot pass the message to syslogd it will attempt to write the message to the con- sole (/dev/console). LOG_NDELAY Open the connection to syslogd immediately. Normally the open is delayed until the first mes- sage is logged. Useful for programs that need to manage the order in which file descriptors are allocated. LOG_PERROR Write the message to standard error output as well to the system log. LOG_PID Log the process id with each message: 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: LOG_AUTH The authorization system: login(1), su(1), getty(8), etc. LOG_AUTHPRIV The same as LOG_AUTH , but logged to a file readable only by selected individuals. LOG_CRON The clock daemon. LOG_DAEMON System daemons, such as routed(8), that are not provided for explicitly by other facilities. LOG_KERN Messages generated by the kernel. These cannot be generated by any user processes. LOG_LPR The line printer spooling system: lpr(1), lpc(8), lpd(8), etc. LOG_MAIL The mail system. LOG_NEWS The network news system. LOG_SYSLOG Messages generated internally by syslogd(8). LOG_USER Messages generated by random user processes. This is the default facility identifier if none is specified. LOG_UUCP The uucp system. LOG_LOCAL0 Reserved for local use. Similarly for LOG_LOCAL1 through LOG_LOCAL7. The closelog function can be 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 closelog(), openlog(), syslog() and vsyslog() 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_DAEMON); setlogmask(LOG_UPTO(LOG_ERR)); syslog(LOG_INFO, "Connection from host %d", CallingHost); syslog(LOG_INFO|LOG_LOCAL2, "foobar error: %m");
logger(1), syslogd(8)
Under 2.11BSD the logfile /usr/adm/messages is used if a non networking kernel has been booted. That file must be publically writeable in this case.
These functions appeared in 4.2BSD. 4.2 Berkeley Distribution April 1, 1995 SYSLOG(3)
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