PHP - 传递给if条件的对象

Question

What exactly is going on when you pass an object to an if, like this:

class TestClass {
  ...
}
$obj = new TestClass();

if($obj) { // what exactly is going on here ?
  ...
}

Answer 1

Since your variable is an object, that will always be treated as true- i.e. condition will always pass unless constructor of TestClass will not instantiate object for some reason. You can see type-judging page to see how PHP handles type-casting (in this case, casting to boolean type)