预定义常量

下列常量作为 PHP 核心的一部分总是可用的。

ConstantDescription
LOG_CONSif there is an error while sending data to the system logger, write directly to the system console
LOG_NDELAYopen the connection to the logger immediately
LOG_ODELAY(default) delay opening the connection until the first message is logged
LOG_NOWAIT
LOG_PERRORprint log message also to standard error
LOG_PIDinclude PID with each message
ConstantDescription
LOG_AUTHsecurity/authorization messages (use LOG_AUTHPRIV instead in systems where that constant is defined)
LOG_AUTHPRIVsecurity/authorization messages (private)
LOG_CRONclock daemon (cron and at)
LOG_DAEMONother system daemons
LOG_KERNkernel messages
LOG_LOCAL0 ... LOG_LOCAL7reserved for local use, these are not available in Windows
LOG_LPRline printer subsystem
LOG_MAILmail subsystem
LOG_NEWSUSENET news subsystem
LOG_SYSLOGmessages generated internally by syslogd
LOG_USERgeneric user-level messages
LOG_UUCPUUCP subsystem
ConstantDescription
LOG_EMERGsystem is unusable
LOG_ALERTaction must be taken immediately
LOG_CRITcritical conditions
LOG_ERRerror conditions
LOG_WARNINGwarning conditions
LOG_NOTICEnormal, but significant, condition
LOG_INFOinformational message
LOG_DEBUGdebug-level message
ConstantDescription
DNS_AIPv4 Address Resource
DNS_CAACertification Authority Authorization Resource (available as of PHP 7.0.16 and 7.1.2)
DNS_MXMail Exchanger Resource
DNS_CNAMEAlias (Canonical Name) Resource
DNS_NSAuthoritative Name Server Resource
DNS_PTRPointer Resource
DNS_HINFOHost Info Resource (See IANA's » Operating System Names for the meaning of these values)
DNS_SOAStart of Authority Resource
DNS_TXTText Resource
DNS_ANYAny 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_AAAAIPv6 Address Resource
DNS_ALLIteratively query the name server for each available record type.