(PHP 5 >= 5.3.0, PHP 7)
锟斤拷一锟斤拷锟斤拷锟斤拷锟秸硷拷锟叫ｏ拷锟斤拷 PHP 锟斤拷锟斤拷一锟斤拷锟斤拷锟睫讹拷锟斤拷锟洁、锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷时锟斤拷锟斤拷使锟矫诧拷同锟斤拷锟斤拷锟饺诧拷锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷锟狡★拷锟斤拷锟斤拷锟斤拷锟斤拷锟角斤拷锟斤拷锟斤拷锟斤拷前锟斤拷锟斤拷锟秸硷拷锟叫碉拷锟斤拷锟狡★拷锟斤拷锟斤拷诜锟斤拷锟较低筹拷诓锟斤拷虿话锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷占锟斤拷械锟斤拷锟斤拷锟斤拷锟绞憋拷锟斤拷锟斤拷锟绞癸拷锟斤拷锟饺拷薅锟斤拷锟斤拷疲锟斤拷锟斤拷纾�
Example #1 锟斤拷锟斤拷锟斤拷锟秸硷拷锟叫凤拷锟斤拷全锟斤拷锟斤拷
<?php
namespace A\B\C;
class Exception extends \Exception {}
$a = new Exception('hi'); // $a 锟斤拷锟斤拷 A\B\C\Exception 锟斤拷一锟斤拷锟斤拷锟斤拷
$b = new \Exception('hi'); // $b 锟斤拷锟斤拷 Exception 锟斤拷一锟斤拷锟斤拷锟斤拷
$c = new ArrayObject; // 锟斤拷锟斤拷锟斤拷锟斤拷, 锟揭诧拷锟斤拷 A\B\C\ArrayObject 锟斤拷
?>
锟斤拷锟节猴拷锟斤拷锟酵筹拷锟斤拷锟斤拷说锟斤拷锟斤拷锟斤拷锟角帮拷锟斤拷锟斤拷占锟斤拷胁锟斤拷锟斤拷诟煤锟斤拷锟斤拷锟斤拷锟斤拷锟絇HP 锟斤拷锟剿讹拷使锟斤拷全锟街空硷拷锟叫的猴拷锟斤拷锟斤拷锟斤拷锟斤拷 For functions and constants, PHP will fall back to global functions or constants if a namespaced function or constant does not exist.
Example #2 锟斤拷锟斤拷锟秸硷拷锟叫后备碉拷全锟街猴拷锟斤拷/锟斤拷锟斤拷
<?php
namespace A\B\C;
const E_ERROR = 45;
function strlen($str)
{
return \strlen($str) - 1;
}
echo E_ERROR, "\n"; // 锟斤拷锟� "45"
echo INI_ALL, "\n"; // 锟斤拷锟� "7" - 使锟斤拷全锟街筹拷锟斤拷 INI_ALL
echo strlen('hi'), "\n"; // 锟斤拷锟� "1"
if (is_array('hi')) { // 锟斤拷锟� "is not array"
echo "is array\n";
} else {
echo "is not array\n";
}
?>