预定义常量

下列常量作为 PHP 核心的一部分总是可用的。

openlog() Options

Constant	Description
LOG_CONS	if there is an error while sending data to the system logger, write directly to the system console
LOG_NDELAY	open the connection to the logger immediately
LOG_ODELAY	(default) delay opening the connection until the first message is logged
LOG_NOWAIT
LOG_PERROR	print log message also to standard error
LOG_PID	include PID with each message

openlog() Facilities

Constant	Description
LOG_AUTH	security/authorization messages (use LOG_AUTHPRIV instead in systems where that constant is defined)
LOG_AUTHPRIV	security/authorization messages (private)
LOG_CRON	clock daemon (cron and at)
LOG_DAEMON	other system daemons
LOG_KERN	kernel messages
LOG_LOCAL0 ... LOG_LOCAL7	reserved for local use, these are not available in Windows
LOG_LPR	line printer subsystem
LOG_MAIL	mail subsystem
LOG_NEWS	USENET news subsystem
LOG_SYSLOG	messages generated internally by syslogd
LOG_USER	generic user-level messages
LOG_UUCP	UUCP subsystem

syslog() Priorities (in descending order)

Constant	Description
LOG_EMERG	system is unusable
LOG_ALERT	action must be taken immediately
LOG_CRIT	critical conditions
LOG_ERR	error conditions
LOG_WARNING	warning conditions
LOG_NOTICE	normal, but significant, condition
LOG_INFO	informational message
LOG_DEBUG	debug-level message

dns_get_record() Options

Constant	Description
DNS_A	IPv4 Address Resource
DNS_MX	Mail Exchanger Resource
DNS_CNAME	Alias (Canonical Name) Resource
DNS_NS	Authoritative Name Server Resource
DNS_PTR	Pointer Resource
DNS_HINFO	Host Info Resource (See IANA's » Operating System Names for the meaning of these values)
DNS_SOA	Start of Authority Resource
DNS_TXT	Text Resource
DNS_ANY	Any Resource Record. On most systems this returns all resource records, however it should not be counted upon for critical uses. Try DNS_ALL instead.
DNS_AAAA	IPv6 Address Resource
DNS_ALL	Iteratively query the name server for each available record type.