global variables will be defined when the script that defines them is called.
e.g.
myfile.mel:
<<
global float $a;
global proc myProc()
{
//$a will now be available to use in this function
global float $a;
//assign a value to $a
$a = 1.0;
}
>>
Technical Director - Framestore
Currently working on: Your Highness
IMDB