unexpected modification of a variable

Hi, Is there any way that a variable can be changed within a function without passing it by reference ? I have a code like that: function myfunction($var) { <some code> print_r($var); => prints $var which is an object anotherfunction($var); // call by value print_r($var); => $var has changed } I thought that since there's no reference in any way to the variable it cannot be changed in the function. Am I wrong ?