syslog(3) Library Functions Manual syslog(3) closelog, openlog, syslog, vsyslog - (libc -lc) #include void openlog(const char *ident, int option, int facility); void syslog(int priority, const char *format, ...); void closelog(void); void vsyslog(int priority, const char *format, va_list ap); glibc ( feature_test_macros(7)): vsyslog(): glibc 2.19: _DEFAULT_SOURCE glibc 2.19 : _BSD_SOURCE openlog() openlog() . ident . ident (NULL) . ( POSIX.1-2008 ident .) option openlog() syslog(). facility syslog(). option facility . openlog() syslog() ident (NULL). syslog() vsyslog() syslog() syslogd(8). priority OR facility level ( ). facility priority openlog() openlog() LOG_USER. format printf(3) format %m strerror(errno). . vsyslog() syslog() stdarg(3). closelog() closelog() . closelog() . option option openlog() OR : LOG_CONS . LOG_NDELAY ( ). chroot(2) . LOG_NOWAIT . ( C .) LOG_ODELAY LOG_NDELAY syslog(). ( .) LOG_PERROR ( POSIX.1-2001 POSIX.1-2008.) stderr. LOG_PID PID . facility facility . . LOG_AUTH / LOG_AUTHPRIV / () LOG_CRON (cron at) LOG_DAEMON LOG_FTP ftp LOG_KERN ( ) LOG_LOCAL0 LOG_LOCAL7 LOG_LPR LOG_MAIL LOG_NEWS USENET LOG_SYSLOG syslogd(8) LOG_USER () LOG_UUCP UUCP . : LOG_EMERG LOG_ALERT LOG_CRIT LOG_ERR LOG_WARNING LOG_NOTICE LOG_INFO LOG_DEBUG setlogmask(3) . attributes(7). +----------------------+------------------------------------+----------------------------------------------------------------------------------------+ | | | | +----------------------+------------------------------------+----------------------------------------------------------------------------------------+ |openlog(), closelog() | | MT-Safe | +----------------------+------------------------------------+----------------------------------------------------------------------------------------+ |syslog(), vsyslog() | | (MT-Safe) | +----------------------+------------------------------------+----------------------------------------------------------------------------------------+ syslog() openlog() closelog() POSIX.1-2008. vsyslog() . syslog() 4.2BSD SUSv2 POSIX.1-2001. openlog() closelog() 4.3BSD SUSv2 POSIX.1-2001. vsyslog() 4.3BSD-Reno. POSIX.1-2001 LOG_USER LOG_LOCAL* facility. LOG_AUTHPRIV LOG_FTP facility UNIX. LOG_PERROR option POSIX.1-2001 POSIX.1-2008 UNIX. ident openlog() . syslog() . . : syslog(priority, "%s", string); journalctl(1) logger(1) setlogmask(3) syslog.conf(5) syslogd(8) 3 . . : . 6.18 8 2026 syslog(3)