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The following examples show how results differ when a subroutine or function uses or does not use
PROCEDURE.
The next two examples are the same, except they use functions rather than subroutines.
/******************************* REXX ********************************/
/* This program uses a PROCEDURE instruction to protect the */
/* variables within its subroutine. */
/*********************************************************************/
number1 = 10
CALL subroutine
SAY number1 number2 /* Produces 10 NUMBER2 */
EXIT
subroutine: PROCEDURE
number1 = 7
number2 = 5
RETURN
Figure 33. Example of Subroutine Using the PROCEDURE Instruction
/******************************* REXX ********************************/
/* This program does not use a PROCEDURE instruction to protect the */
/* variables within its subroutine. */
/*********************************************************************/
number1 = 10
CALL subroutine
SAY number1 number2 /* Produces 7 5 */
EXIT
subroutine:
number1 = 7
number2 = 5
RETURN
Figure 34. Example of Subroutine without the PROCEDURE Instruction
/******************************* REXX ********************************/
/* This program uses a PROCEDURE instruction to protect the */
/* variables within its function. */
/*********************************************************************/
number1 = 10
SAY pass() number2 /* Produces 7 NUMBER2 */
EXIT
pass: PROCEDURE
number1 = 7
number2 = 5
RETURN number1
Figure 35. Example of Function Using the PROCEDURE Instruction
Writing Subroutines and Functions
Chapter 6. Writing Subroutines and Functions 63