The symbols referred to in this section are declared in the file `syslog.h'.
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
LOG_MAIL
LOG_DAEMON
LOG_AUTH
LOG_SYSLOG
LOG_LPR
LOG_NEWS
LOG_UUCP
LOG_CRON
LOG_AUTHPRIV
LOG_FTP
LOG_LOCAL0
LOG_LOCAL1
LOG_LOCAL2
LOG_LOCAL3
LOG_LOCAL4
LOG_LOCAL5
LOG_LOCAL6
LOG_LOCAL7
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. See section Syslog Example.
The possible values for the priority code are (macros):
LOG_EMERG
LOG_ALERT
LOG_CRIT
LOG_ERR
LOG_WARNING
LOG_NOTICE
LOG_INFO
LOG_DEBUG
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);
This is functionally identical to syslog
, with the BSD style variable
length argument.
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