PHP constant()函数

constant()函数返回一个常量的值

define('PI', 3.1415926);echo PI;//3.1415926echo '<br/>';echo "PI";//PIecho '<br/>';echo constant('PI');//3.1415926

for:

echo "默认的错误处理模式：".$pdo->getAttribute(PDO::ATTR_ERRMODE);echo "<hr/>";$pdo->setAttribute(PDO::ATTR_AUTOCOMMIT, 0);echo "自动提交".$pdo->getAttribute(PDO::ATTR_AUTOCOMMIT);echo "<hr/>";

$attrArr=array('AUTOCOMMIT','ERRMODE','CASE','PERSISTENT','SERVER_INFO','SERVER_VERSION');foreach ($attrArr as $attr){echo "PDO::ATTR_$attr: ";echo $pdo->getAttribute(constant("PDO::ATTR_$attr"))."<br/>";}

study:

constant()




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