Procedure-Related Statements


 Defining a procedure
 --------------------
 FUNCTION...
 END FUNCTION
 Marks the beginning and end, respectively, of a FUNCTION procedure.

 SUB...END SUB
 Marks the beginning and end, respectively, of a SUB procedure.


 Calling a procedure
 -------------------
 CALL
 Transfers control to a BASIC SUB procedure, or to a procedure written in
 another programming language and compiled separately. (The CALL keyword is
 optional if a DECLARE statement is used.)


 Exiting from a procedure
 ------------------------
 EXIT FUNCTION
 Provides an alternative way to exit a FUNCTION procedure.

 EXIT SUB
 Provides an alternative way to exit a SUB procedure.


 Declaring a reference to a procedure
 ------------------------------------
 DECLARE
 Declares a FUNCTION or SUB procedure and, optionally, specifies the number
 and type of its parameters.


 Sharing variables among modules, procedures, or programs
 --------------------------------------------------------
 COMMON
 Shares variables among separate modules. When used with the SHARED
 attribute, COMMON blocks share variables among different procedures in the
 same module. When used with a blank (unnamed) COMMON block, variables pass
 from current program to new program when control is transferred with the
 CHAIN statement.

 SHARED
 When used with the COMMON, DIM, or REDIM statement at the module level (for
 example, DIM SHARED), shares variables with every SUB or FUNCTION procedure
 in a single module.
 When used by itself within a procedure, shares variables between that
 procedure and the module-level code.

 Preserving variable values
 --------------------------
 STATIC
 Forces variables to be local to a procedure or DEF FN function and preserves
 the value stored in the variable if the procedure or function is exited,
 then called again.