opcode

问题 In Java\'s String class, the trim method contains this: int off = offset; /* avoid getfield opcode */ char[] val = value; /* avoid getfield opcode */ I\'m a bit puzzled by the comment \"avoid getfield opcode\" ... What does this mean? (I take it this avoids the use of getfield in the bytecode but why is this a Good Thing [TM]?) Is it to prevent object creation in case trim doesn\'t do anything (and hence this is returned) or? 回答1: My guess is that the point is to copy the values into local

问题 What does a \\ do in PHP? For example, CSRF4PHP has \\FALSE , \\session_id , and \\Exception : public function __construct($timeout=300, $acceptGet=\\FALSE){ $this->timeout = $timeout; if (\\session_id()) { $this->acceptGet = (bool) $acceptGet; } else { throw new \\Exception(\'Could not find session id\', 1); } } 回答1: \ (backslash) is the namespace separator in PHP 5.3. A \ before the beginning of a function represents the Global Namespace. Putting it there will ensure that the function