SUB...END SUB - a procedure statement that marks the beginning and
                end of a subprogram
Syntax
  SUB globalname[parameterlist][STATIC]
    [statements]
  [EXIT SUB]
    [statements]
  END SUB
 
    - globalname is a variable name up to 40 characters long, which does
      not appear in any other SUB or FUNCTION statement in the same program
    - parameterlist contains the names of the simple variables and arrays
      passed to the SUB when it is called (see <DETAILS> for the syntax of
      the parameter list)
    - use the optional STATIC keyword to preserve local variable values
      between calls
 
See also  <DECLARE>  <CALL>  <SHARED>  <STATIC STATEMENT>