|SYSLOG(3)||Linux Programmer's Manual||SYSLOG(3)|
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
Since glibc 2.19:
Glibc 2.19 and earlier:
_BSD_SOURCE syslogd(8). The priority argument is formed by ORing together a facility value and a level value (described below). If no facility value is ORed into priority, then the default value set by openlog() is used, or, if there was no preceding openlog() call, a default of LOG_USER is employed. The remaining arguments are a format, as in printf(3), and any arguments required by the format, except that the two-character sequence %m will be replaced by the error message string strerror(errno). The format string need not include a terminating newline character. The function vsyslog() performs the same task as syslog() with the difference that it takes a set of arguments which have been obtained using the stdarg(3) variable argument list macros.
- Write directly to the system console if there is an error while sending to the system logger.
- Open the connection immediately (normally, the connection is opened when the first message is logged). This may be useful, for example, if a subsequent chroot(2) would make the pathname used internally by the logging facility unreachable.
- Don't wait for child processes that may have been created while logging the message. (The GNU C library does not create a child process, so this option has no effect on Linux.)
- The converse of LOG_NDELAY; opening of the connection is delayed until syslog() is called. (This is the default, and need not be specified.)
- (Not in POSIX.1-2001 or POSIX.1-2008.) Also log the message to stderr.
- Include the caller's PID with each message.
- security/authorization messages
- security/authorization messages (private)
- clock daemon (cron and at)
- system daemons without separate facility value
- ftp daemon
- kernel messages (these can't be generated from user processes)
- LOG_LOCAL0 through LOG_LOCAL7
- reserved for local use
- line printer subsystem
- mail subsystem
- USENET news subsystem
- messages generated internally by syslogd(8)
- LOG_USER (default)
- generic user-level messages
- UUCP subsystem
- system is unusable
- action must be taken immediately
- critical conditions
- error conditions
- warning conditions
- normal, but significant, condition
- informational message
- debug-level message
|openlog (), closelog ()||Thread safety||MT-Safe|
|syslog (), vsyslog ()||Thread safety||MT-Safe env locale|
syslog(priority, "%s", string);
journalctl(1), logger(1), setlogmask(3), syslog.conf(5), syslogd(8)