Sometimes when developing in PHP in large applications searching for function (without IDE) in all the files becomes boring. So I was looking for quick solution of this. By searching few minutes I found great solution.
There is a built-in PHP class ReflectionFunction
Example of ReflectionFunction Class
$r = new ReflectionFunction('selected'); // ReflectionFunction is a PHP in-built class
echo $file = $r->getFileName(); // getFileName() is inherited method.
echo $startLine = $r->getStartLine(); // getStartLine() is inherited method.
Here in first line selected is function name I want to search where it’s declared.