锟斤拷锟斤拷锟斤拷一锟斤拷锟斤拷值锟侥憋拷识锟斤拷锟斤拷锟斤拷锟街ｏ拷锟斤拷锟斤拷同锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷示锟侥ｏ拷锟节脚憋拷执锟斤拷锟节硷拷锟街碉拷锟斤拷芨谋洌拷锟斤拷锟斤拷锟轿斤拷锟�魔锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷实锟斤拷锟角筹拷锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷默锟斤拷为锟斤拷小写锟斤拷锟叫★拷锟斤拷统锟较筹拷锟斤拷锟斤拷识锟斤拷锟斤拷锟角达拷写锟侥★拷
锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷锟轿猴拷 PHP 锟斤拷签锟斤拷循同锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷锟津。合凤拷锟侥筹拷锟斤拷锟斤拷锟斤拷锟斤拷母锟斤拷锟铰伙拷锟竭匡拷始锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷魏锟斤拷锟侥革拷锟斤拷锟斤拷只锟斤拷禄锟斤拷摺锟斤拷锟斤拷锟斤拷锟斤拷锟绞斤拷锟斤拷锟斤拷锟斤拷锟斤拷模锟�[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*锟斤拷
锟斤拷渭锟�锟矫伙拷锟秸硷拷锟斤拷锟斤拷指锟斤拷锟斤拷
Example #1 锟较凤拷锟斤拷欠锟斤拷某锟斤拷锟斤拷锟�
<?php
// 锟较凤拷锟侥筹拷锟斤拷锟斤拷
define("FOO", "something");
define("FOO2", "something else");
define("FOO_BAR", "something more");
// 锟角凤拷锟侥筹拷锟斤拷锟斤拷
define("2FOO", "something");
// 锟斤拷锟斤拷亩锟斤拷锟斤拷呛戏锟斤拷模锟斤拷锟接︼拷帽锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷锟�(锟皆讹拷锟藉常锟斤拷锟斤拷要锟斤拷__锟斤拷头)
// 也锟斤拷锟斤拷锟斤拷一锟斤拷PHP锟结定锟斤拷一锟斤拷__FOO__锟斤拷魔锟斤拷锟斤拷锟斤拷
// 锟斤拷锟斤拷锟酵伙拷锟斤拷锟斤拷拇锟斤拷锟斤拷锟斤拷突
define("__FOO__", "something");
?>
Note: 锟斤拷锟斤拷锟斤，锟斤拷母指锟斤拷锟斤拷 a-z锟斤拷A-Z锟斤拷锟皆硷拷锟斤拷 127 锟斤拷 255锟斤拷0x7f-0xff锟斤拷锟斤拷 ASCII 锟街凤拷锟斤拷
锟斤拷 superglobals 一锟斤拷锟斤拷锟斤拷锟斤拷锟侥凤拷围锟斤拷全锟街的★拷锟斤拷锟矫癸拷锟斤拷锟斤拷锟斤拷锟斤拷涂锟斤拷锟斤拷诮疟锟斤拷锟斤拷魏蔚胤锟斤拷锟斤拷食锟斤拷锟斤拷锟斤拷泄锟斤拷锟斤拷锟斤拷锟斤拷锟侥革拷锟斤拷锟斤拷息锟斤拷锟侥讹拷锟街诧拷锟叫碉拷锟斤拷锟斤拷锟斤拷围锟斤拷