预定义常量
下列常量作为 PHP 核心的一部分总是可用的。
| 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 |
| 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 |
| 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 |
| Constant | Description |
|---|---|
DNS_A |
IPv4 Address Resource |
DNS_CAA |
Certification Authority Authorization Resource (available as of PHP 7.0.16 and 7.1.2) |
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. |
