Question about C++ like macros on PHP

Hi list, For debugging purposes I want to send to a function the line and file where it is called. The problem is that I want these parameters to be added to function as default parameters (changing all function calls would not be an option for me) function my_func( $param, $line = __LINE__, $file = __FILE__ ) { ... } won't work as it always gets the file and line where function is defined. Also I don't want to change all function calls to put __LINE__ and __FILE__ parameters. I looked into assert too, but I have to change again all function calls to be assert( "my_func(...)" ); which again will be a pain in the a... as this function is often called in every scripts... Any1 has any ideea about it? Thnx, Andrei