PROLOG¶

This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.

NAME¶

syslog.h — definitions for system error logging

SYNOPSIS¶

#include <syslog.h>

DESCRIPTION¶

The <syslog.h> header shall define the following symbolic constants, zero or more of which may be OR'ed together to form the logopt option of openlog():

LOG_PID

Log the process ID with each message.

LOG_CONS

Log to the system console on error.

LOG_NDELAY

Connect to syslog daemon immediately.

LOG_ODELAY

Delay open until syslog() is called.

LOG_NOWAIT

Do not wait for child processes.

The <syslog.h> header shall define the following symbolic constants for use as the facility argument to openlog():

LOG_KERN

Reserved for message generated by the system.

LOG_USER

Message generated by a process.

LOG_MAIL

Reserved for message generated by mail system.

LOG_NEWS

Reserved for message generated by news system.

LOG_UUCP

Reserved for message generated by UUCP system.

LOG_DAEMON

Reserved for message generated by system daemon.

LOG_AUTH

Reserved for message generated by authorization daemon.

LOG_CRON

Reserved for message generated by clock daemon.

LOG_LPR

Reserved for message generated by printer system.

LOG_LOCAL0

Reserved for local use.

LOG_LOCAL1

Reserved for local use.

LOG_LOCAL2

Reserved for local use.

LOG_LOCAL3

Reserved for local use.

LOG_LOCAL4

Reserved for local use.

LOG_LOCAL5

Reserved for local use.

LOG_LOCAL6

Reserved for local use.

LOG_LOCAL7

Reserved for local use.

The <syslog.h> header shall define the following macros for constructing the maskpri argument to setlogmask(). The following macros expand to an expression of type int when the argument pri is an expression of type int:

LOG_MASK(pri)

A mask for priority pri.

The <syslog.h> header shall define the following symbolic constants for use as the priority argument of syslog():

LOG_EMERG

A panic condition was reported to all processes.

LOG_ALERT

A condition that should be corrected immediately.

LOG_CRIT

A critical condition.

LOG_ERR

An error message.

LOG_WARNING

A warning message.

LOG_NOTICE

A condition requiring special handling.

LOG_INFO

A general information message.

LOG_DEBUG

A message useful for debugging programs.

The following shall be declared as functions and may also be defined as macros. Function prototypes shall be provided.

void  closelog(void);
void  openlog(const char *, int, int);
int   setlogmask(int);
void  syslog(int, const char *, ...);

The following sections are informative.

APPLICATION USAGE¶

None.

RATIONALE¶

None.

FUTURE DIRECTIONS¶

None.

SEE ALSO¶

The System Interfaces volume of POSIX.1‐2017, closelog()

COPYRIGHT¶

Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source files to man page format. To report such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .