syslog(3) - phpMan

Command: man perldoc info search(apropos)  


SYSLOG(3)                  Linux Programmer's Manual                 SYSLOG(3)



NAME
       closelog, openlog, syslog, vsyslog - send messages to the system logger

SYNOPSIS
       #include <syslog.h>

       void openlog(const char *ident, int option, int facility);
       void syslog(int priority, const char *format, ...);
       void closelog(void);

       #include <stdarg.h>

       void vsyslog(int priority, const char *format, va_list ap);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       vsyslog(): _BSD_SOURCE

DESCRIPTION
       closelog() closes the descriptor being used to write to the system logger.  The use
       of closelog() is optional.

       openlog() opens a connection to the  system  logger  for  a  program.   The  string
       pointed to by ident is prepended to every message, and is typically set to the pro-
       gram name.  The option argument specifies flags  which  control  the  operation  of
       openlog()  and  subsequent  calls to syslog().  The facility argument establishes a
       default to be used if none is specified in subsequent calls  to  syslog().   Values
       for option and facility are given below.  The use of openlog() is optional; it will
       automatically be called by syslog() if necessary, in which case ident will  default
       to NULL.

       syslog()  generates  a  log  message, which will be distributed by syslogd(8).  The
       priority argument is formed by ORing the facility and the level  values  (explained
       below).   The  remaining  arguments are a format, as in printf(3) and any arguments
       required by the format, except that the two character sequence %m will be  replaced
       by  the  error  message string strerror(errno).  A trailing newline may be added if
       needed.

       The function vsyslog() performs the same task as syslog() with the difference  that
       it  takes  a set of arguments which have been obtained using the stdarg(3) variable
       argument list macros.

       The subsections below list the parameters used to set the values of option,  facil-
       ity, and priority.

   option
       The option argument to openlog() is an OR of any of these:

       LOG_CONS       Write  directly to system console if there is an error while sending
                      to system logger.

       LOG_NDELAY     Open the connection immediately (normally, the connection is  opened
                      when the first message is logged).

       LOG_NOWAIT     Don't wait for child processes that may have been created while log-
                      ging the message.  (The GNU C library does not create a  child  pro-
                      cess, so this option has no effect on Linux.)

       LOG_ODELAY     The  converse  of  LOG_NDELAY;  opening of the connection is delayed
                      until syslog() is called.  (This is the default,  and  need  not  be
                      specified.)

       LOG_PERROR     (Not in POSIX.1-2001.)  Print to stderr as well.

       LOG_PID        Include PID with each message.

   facility
       The  facility  argument is used to specify what type of program is logging the mes-
       sage.  This lets the configuration file specify that messages from different facil-
       ities will be handled differently.

       LOG_AUTH       security/authorization   messages   (DEPRECATED   Use   LOG_AUTHPRIV
                      instead)

       LOG_AUTHPRIV   security/authorization messages (private)

       LOG_CRON       clock daemon (cron and at)

       LOG_DAEMON     system daemons without separate facility value

       LOG_FTP        ftp daemon

       LOG_KERN       kernel messages (these can't be generated from user processes)

       LOG_LOCAL0 through LOG_LOCAL7
                      reserved for local use

       LOG_LPR        line printer subsystem

       LOG_MAIL       mail subsystem

       LOG_NEWS       USENET news subsystem

       LOG_SYSLOG     messages generated internally by syslogd(8)

       LOG_USER (default)
                      generic user-level messages

       LOG_UUCP       UUCP subsystem

   level
       This determines the importance of  the  message.   The  levels  are,  in  order  of
       decreasing importance:

       LOG_EMERG      system is unusable

       LOG_ALERT      action must be taken immediately

       LOG_CRIT       critical conditions

       LOG_ERR        error conditions

       LOG_WARNING    warning conditions

       LOG_NOTICE     normal, but significant, condition

       LOG_INFO       informational message

       LOG_DEBUG      debug-level message

       The  function  setlogmask(3)  can  be  used to restrict logging to specified levels
       only.

CONFORMING TO
       The functions openlog(), closelog(), and syslog() (but not vsyslog()) are specified
       in SUSv2 and POSIX.1-2001.  POSIX.1-2001 specifies only the LOG_USER and LOG_LOCAL*
       values for facility.  However, with the exception of LOG_AUTHPRIV and LOG_FTP,  the
       other facility values appear on most Unix systems.  The LOG_PERROR value for option
       is not specified by POSIX.1-2001, but is available in most versions of Unix.

NOTES
       The argument ident in the call of openlog() is probably stored as-is.  Thus, if the
       string  it  points to is changed, syslog() may start prepending the changed string,
       and if the string it points to ceases to exist, the results  are  undefined.   Most
       portable is to use a string constant.

       Never pass a string with user-supplied data as a format, use the following instead:

           syslog(priority, "%s", string);

SEE ALSO
       logger(1), setlogmask(3), rsyslog.conf(5), syslogd(8)

COLOPHON
       This page is part of release 3.22 of the Linux man-pages project.  A description of
       the  project, and information about reporting bugs, can be found at http://www.ker-
       nel.org/doc/man-pages/.



Linux                             2008-11-12                         SYSLOG(3)

Generated by $Id: phpMan.php,v 4.55 2007/09/05 04:42:51 chedong Exp $ Author: Che Dong
On Apache
Under GNU General Public License
2017-12-16 01:19 @127.0.0.1 CrawledBy CCBot/2.0 (http://commoncrawl.org/faq/)
Valid XHTML 1.0!Valid CSS!