When you declare a function in your plugin code which has already been declared previously in either WordPress code or in one of the plugins. ����� ���� ������ ����� �������� ������� ����� �� �� ������� ���� ��� �� ����� �� ��� ���� ��� WordPress ����� �� �� ����� �� ������. To prevent this you should declare your functions like this: ���� ��� ��� ���� �� ���� ������ ��� ��� : 

 if(!function_exists('your_function_name')) {     function your_function_name() {         //.... ��� ���� ������� � (! function_exists ( 'your_function_name')) (����� your_function_name () (//.... Function code     } } ����� �������))

It is a good idea to always define and consistently use a namespace. ���� ���� ���� ������ ����� ��������� ������� ������. For example we name all our plugin functions prefixed with tg, to identify our company. ���� ���� ������ ��� ����� ��� �� ����� �������� ������� �� prefixed tg � ������ ������.