module Make_var_type:
get and set functions to access variables
      of type T.t. Call it like
         module Foo_var = 
           Make_var_type(struct type t = foo end)
      
      and use Foo_var.get and Foo_var.set to access the shared
      variables of type foo. These functions can also raise the exception
      Sharedvar_not_found (unlike the primitive accessors above).
      The variable must have been created with enc:true, e.g.
          let ok = create_var ~enc:true "name"
      | Parameters: | 
 | 
type 
val get : string -> tval set : string -> t -> unit