openlog man page on DigitalUNIX

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syslog(3)							     syslog(3)

       closelog,  openlog,  setlogmask, syslog, closelog_r, openlog_r, setlog‐
       mask_r, syslog_r - Control system log

       #include <syslog.h>

       void closelog(
	       void ); void openlog(
	       const char *id,
	       int log_option,
	       int facility ); int setlogmask(
	       int mask_priority ); void syslog(
	       int priority,
	       const char *format, ...	); void closelog_r(
	       struct syslog_data *syslog_data ); int openlog_r(
	       const char *id,
	       int log_option,
	       int facility,
	       struct syslog_data *syslog_data ); int setlogmask_r(
	       int mask_priority,
	       struct syslog_data *syslog_data ); int syslog_r(
	       int priority,
	       struct syslog_data *syslog_data,
	       const char *format, ...	);

       The following function declarations do not conform to current standards
       and are supported only for backward compatibility.

       int openlog(
	       const char *id,
	       int log_option,
	       int facility ); int syslog(
	       int priority,
	       const char *format, ...	);

       Standard C Library (libc)

       Interfaces  documented on this reference page conform to industry stan‐
       dards as follows:

       closelog(), openlog(), setlogmask(), syslog():  XSH4.2

       Refer to the standards(5) reference page	 for  more  information	 about
       industry standards and associated tags.

       Specifies  a string that is attached to the beginning of every message.
       Specifies logging options. Values of the log_option parameter  include:
       Logs  the process ID with each message. This option is useful for iden‐
       tifying daemons.	 Sends messages to the console if unable to send  them
       to syslogd. This option is useful in daemon processes that have no con‐
       trolling	 terminal.   Opens  the	 connection  to	 syslogd  immediately,
       instead	of when the first message is logged. This option is useful for
       programs that need to manage the order in which	file  descriptors  are

	      [Tru64  UNIX]  This  option  is  required for programs using the
	      chroot system call.  Delays opening the  connection  until  sys‐
	      log()  is	 called.  Logs messages to the console without waiting
	      for child processes that are forked. Use this  option  for  pro‐
	      cesses  that  enable  notification  of termination of child pro‐
	      cesses through SIGCHLD; otherwise,  the  syslog()	 function  may
	      block, waiting for a child process whose exit status has already
	      been collected.  Specifies the facility that generated the  mes‐
	      sage, which is one of the following: [Tru64 UNIX]	 Messages gen‐
	      erated by the kernel. These cannot be generated by any user pro‐
	      cesses.	Messages  generated  by	 user  processes.  This is the
	      default facility when none is specified.	[Tru64 UNIX]  Messages
	      generated	 by the mail system.  [Tru64 UNIX]  Messages generated
	      by system daemons.   [Tru64  UNIX]  Messages  generated  by  the
	      authorization  system: login, su, and so on.  [Tru64 UNIX]  Mes‐
	      sages generated by the line  printer  spooling  system.	[Tru64
	      UNIX]  Messages  generated by remote file systems.  Reserved for
	      local use.

	      This parameter encodes a default facility from the previous list
	      to be assigned to messages that do not have an explicit facility
	      encoded.	Messages are tagged with codes indicating the type  of
	      priority	for  each.   The  priority  parameter  is encoded as a
	      facility (as previously listed), which describes the part of the
	      system  generating  the message, and as a level, which indicates
	      the severity of the message. The level of severity  is  selected
	      from  the	 following list: A panic condition was reported to all
	      users.  Specifies a condition to be corrected  immediately,  for
	      example, a corrupted database.  Specifies a critical conditions,
	      for example, hard device errors.	Specifies  errors.   Specifies
	      warning  messages.  Specifies that it is not an error condition,
	      but a condition requiring special handling.   Specifies  general
	      information messages.  Specifies messages containing information
	      useful in debugging  a  program.	 Similar  to  the  printf  fmt
	      string,  with  the difference that %m is replaced by the current
	      error message obtained from errno.  A trailing  newline  can  be
	      added  to	 the  message  if needed. The value parameters are the
	      same as the value parameters of the printf()  function.  Callers
	      of  syslog()  must  ensure  that	the message is not longer than
	      LINE_MAX bytes. Results are unspecified if  syslog()  is	called
	      with a message larger than LINE_MAX bytes.  Specifies a bit mask
	      used to set the new log priority mask and	 return	 the  previous
	      mask.  The LOG_MASK and LOG_UPTO macros in the sys/syslog.h file
	      are  used	 to  create  the  priority  mask.   [Tru64  UNIX]  The
	      closelog_r(),  openlog_r(), setlogmask_r(), and syslog_r() func‐
	      tions use this opaque structure.

       The syslog() function writes messages to the system log	maintained  by
       the syslogd daemon.

       The syslogd daemon reads messages and writes them to the system console
       or to a log file, or forwards them to the syslogd daemon on the	appro‐
       priate host.

       If  the syslog() function cannot pass the message to syslogd, it writes
       the message on /dev/console, provided the LOG_CONS option is set.

       If special processing is required, the openlog() function can  be  used
       to initialize the log file.

       [Tru64  UNIX]  If a program is using the chroot system call, the syslog
       routine will not work correctly unless the program calls the openlog or
       openlog_r routine prior to making the call to chroot .

       The closelog() function closes the log file.

       The setlogmask() function uses the bit mask in the mask_priority param‐
       eter to set the new log priority mask and returns  the  previous	 mask.
       Logging	is  enabled  for  the levels indicated by the bits in the mask
       that are set and is disabled where the bits are not set.	  The  default
       mask  allows  all  priorities to be logged. If the syslog() function is
       called with a priority mask that does not allow logging of  that	 level
       of message, then the function returns without logging the message.

       The  log_option,	 facility,  and	 priority  macros  are	defined in the
       <sys/syslog_pri.h> file.

       [Tru64 UNIX]  The closelog_r(), openlog_r, syslog_r,  and  setlogmask_r
       functions  use  the  syslog_data	 structure  to	maintain syslog access
       state. They can be used in place of  closelog(),	 openlog(),  syslog(),
       and  setlogmask()  when	it  is	necessary to have a unique set of IDs,
       options, facilities, or masks for each thread in a multithreaded appli‐
       cation.	The  data  object  syslog_data	should	be initialized to SYS‐

       [XSH4.2]	 The setlogmask() function returns the previous	 log  priority
       mask.  The  closelog(),	openlog(),  and	 syslog()  functions return no

       [Tru64 UNIX]  The backward-compatible version of the syslog()  function
       returns a value of -1 if either the priority mask excludes this message
       from being logged, or if an error occurs and it is impossible  to  send
       the message to the syslogd daemon or to the system console.

       [Tru64  UNIX]  Upon successful completion, the backward-compatible ver‐
       sion of the openlog() function returns a value of 0 (zero).  Otherwise,
       a value of -1 is returned and errno is set to indicate the error.

       Functions: profil(2)

       Standards: standards(5)


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