The call stack displays the list of nested functions whose code is being executed at the moment (shown in the figure B.11). Each line of the call stack (also called a stack frame) contains the full name of the class, the name of the method within the class and line number. Moving down the stack, you can better understand the current execution state of the program.
For example, in figure B.11, you can see that currently the
is being executed, and this method was in turn called by the
and so on. We can walk the call stack until we reach the index.php file, which is the top of the stack.
You can also click a stack frame to see the place of the code that is currently being executed.