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(libc.info)syslog; vsyslog

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syslog, vsyslog
---------------

   The symbols referred to in this section are declared in the file
`syslog.h'.

 - Function: void syslog (int FACILITY_PRIORITY, char *FORMAT, ...)
     `syslog' submits a message to the Syslog facility.  It does this by
     writing to the Unix domain socket `/dev/log'.

     `syslog' submits the message with the facility and priority
     indicated by FACILITY_PRIORITY.  The macro `LOG_MAKEPRI' generates
     a facility/priority from a facility and a priority, as in the
     following example:

          LOG_MAKEPRI(LOG_USER, LOG_WARNING)

     The possible values for the facility code are (macros):

    `LOG_USER'
          A miscellaneous user process

    `LOG_MAIL'
          Mail

    `LOG_DAEMON'
          A miscellaneous system daemon

    `LOG_AUTH'
          Security (authorization)

    `LOG_SYSLOG'
          Syslog

    `LOG_LPR'
          Central printer

    `LOG_NEWS'
          Network news (e.g. Usenet)

    `LOG_UUCP'
          UUCP

    `LOG_CRON'
          Cron and At

    `LOG_AUTHPRIV'
          Private security (authorization)

    `LOG_FTP'
          Ftp server

    `LOG_LOCAL0'
          Locally defined

    `LOG_LOCAL1'
          Locally defined

    `LOG_LOCAL2'
          Locally defined

    `LOG_LOCAL3'
          Locally defined

    `LOG_LOCAL4'
          Locally defined

    `LOG_LOCAL5'
          Locally defined

    `LOG_LOCAL6'
          Locally defined

    `LOG_LOCAL7'
          Locally defined

     Results are undefined if the facility code is anything else.

     *note:* `syslog' recognizes one other facility code: that of the
     kernel.  But you can't specify that facility code with these
     functions.  If you try, it looks the same to `syslog' as if you are
     requesting the default facility.  But you wouldn't want to anyway,
     because any program that uses the GNU C library is not the kernel.

     You can use just a priority code as FACILITY_PRIORITY.  In that
     case, `syslog' assumes the default facility established when the
     Syslog connection was opened.  Note: Syslog Example.

     The possible values for the priority code are (macros):

    `LOG_EMERG'
          The message says the system is unusable.

    `LOG_ALERT'
          Action on the message must be taken immediately.

    `LOG_CRIT'
          The message states a critical condition.

    `LOG_ERR'
          The message describes an error.

    `LOG_WARNING'
          The message is a warning.

    `LOG_NOTICE'
          The message describes a normal but important event.

    `LOG_INFO'
          The message is purely informational.

    `LOG_DEBUG'
          The message is only for debugging purposes.

     Results are undefined if the priority code is anything else.

     If the process does not presently have a Syslog connection open
     (i.e.  it did not call `openlog'), `syslog' implicitly opens the
     connection the same as `openlog' would, with the following defaults
     for information that would otherwise be included in an `openlog'
     call: The default identification string is the program name.  The
     default default facility is `LOG_USER'.  The default for all the
     connection options in OPTIONS is as if those bits were off.
     `syslog' leaves the Syslog connection open.

     If the `dev/log' socket is not open and connected, `syslog' opens
     and connects it, the same as `openlog' with the `LOG_NDELAY'
     option would.

     `syslog' leaves `/dev/log' open and connected unless its attempt
     to send the message failed, in which case `syslog' closes it (with
     the hope that a future implicit open will restore the Syslog
     connection to a usable state).

     Example:


          #include <syslog.h>
          syslog (LOG_MAKEPRI(LOG_LOCAL1, LOG_ERROR),
                  "Unable to make network connection to %s.  Error=%m", host);


 - Function: void vsyslog (int FACILITY_PRIORITY, char *FORMAT, va_list
          arglist)
     This is functionally identical to `syslog', with the BSD style
     variable length argument.