Sheltran - PERFORM and PROC

Form:

C     To invoke a procedure section: 
      PERFORM <procedure name> 
C     To define a procedure section: 
      PROC <procedure name>
         <statement>... 
      CPROC

Notes:

The procedure name must not be longer than 31 characters.
The statements in a PROC may not include:
- STOP or RETURN
- XWHILE, XREPEAT or XFOR unless the corresponding loop is wholly included within the range of the PROC-CPROC construct.
A procedure section may only be defined in a program after all PERFORMs to that PROC have occurred, i.e. PROCs normally preceed the END statement.
A PERFORM in a FOR-loop causes non-standard FORTRAN to be generated.

Actions:

Whenever a PERFORM statement is encountered, the appropriate statements between PROC and CPROC are executed.

Example:

         . 
         . 
      PERFORM CLFILE
         . 
         . 
         . 
         .
      PROC CLFILE 
         FOR LUN=1,NUNITS
            CLOSE(UNIT=LUN) 
         CFOR
      CPROC