开发需要接触PHP,感觉上手也挺快,在调试PHP中的SESSION时总是出错,

Warning: session_start(): Cannot send session cache limiter - headers already sent (output started at XXX:2) in .php on line 3

类似错,对照源码好像自己没有哪里写错.

php开始符号session在开始前不能有任何字符输出,

header()是一样的

将代码提前,去除前面的空格,就可以了.

-------------------正确

session_start();
$username;
$username = "test";
session_register("username");
echo $_SESSION['username'];
?>

-------------------错误

session_start();
$username;
$username = "test";
session_register("username");
echo $_SESSION['username'];
?>