IBM SC34-5764-01 - Manual (Page 179)

Example:
/* This is the main REXX program */
a.=11; i=13; j=15
i = i + 1
C.5 = 'FRED'
call lucky7
say a. a.1 i j c. c.5
say 'You should see 11 7 14 15 C. FRED'
exit
lucky7:Procedure Expose i j a. c.
/* This exposes I, J, and all variables whose
*/
/* names start with A. or C. */
A.1='7' /* This sets A.1 in the caller's */
/* environment, even if it did not */
/* previously exist. */
return
Variables may be exposed through several generations of routines, if desired, by ensuring that they are
included on all intermediate PROCEDURE instructions.
See the CALL instruction and function descriptions on pages “Purpose” on page 135 and 171 for details
and examples of how routines are called.
PROCEDURE
Chapter 13. Keyword Instructions 157