This function will only read the first value of the stack (that which is "on top"). It will not pop the value, meaning that it can still be read in the future by this function or the ds_stack_pop. If the stack is empty then the function will return the constant undefined, otherwise it will return the real or string value contained in the stack.
|id||The id of the data structure to read from.|
Real, String, or undefined
num = ds_stack_top(control_stack);
The above code will read the value from the stack indexed in the variable "control_stack" and store the return value in the variable "num".