What is the significance of the first parameter to var_Create?

[Peter Tap]

Hi,

I need to share a value across various custom modules. Looks like var_Create/var_Set/var_Get is the way to go. However, I am not sure about the first parameter to these methods. Is this parameter local to each module? To achieve truly global variable, can I simply pass NULL as the first parameter?

Thank you in advance for your help.

Regards,
Peter