execfile in global scope

[v.vayer at gmail.com]

I need to execfile() from a function in order to set value for a global
variable from inside the executed file. I know there are "globals" and
"locals" optional arguments for execfile, but I just can't figure out
how to use them correctly. Here is an example:

Change.py
=========
x = 555

Main.py
=======

def changevar():
    execfile("change.py")

x = 111   # global var
changevar()
print x   # returns 111 instead of 555