functiontrimcoboluppercase

Comparing fields after using intrinsic functions in COBOL

I try to compare two fields in COBOL after using the intrinsic functions upper-case and trim.

When I compare these two fiels without moving the result into new fields the compare says the fields are equal though they are not, e.g. "Wert1" <> "wert1 x" as in my example.

Why does the compare works as I expect when I use fields but not when I use the intrinsic functions directly?

example program:

       program-id. tintr.
       data division.
       working-storage section.

       01  ws-feld1   pic x(10).
       01  ws-feld2   pic x(10).
       01  ws-feld3   pic x(10).
       01  ws-feld4   pic x(10).

       procedure division.

           move "Wert1 " to ws-feld1
           move "wert1 x" to ws-feld2
      *
           display "<" function upper-case(ws-feld1) ">"
           display "<" function upper-case(ws-feld2) ">"
      *
           display "<" function trim(ws-feld1) ">"
           display "<" function trim(ws-feld2) ">"
      *
           display "<" function upper-case
           (function trim(ws-feld1)) ">"
           display "<" function upper-case
           (function trim (ws-feld2)) ">"
      * Compare WS-Feld1/WS-Feld2
           if ws-feld1 = ws-feld2
           then
              display " felder1-2 identical"
           else
              display " felder1-2 not identical"
           end-if
      * Compare Functions uppercase/Trim
           if function upper-case
           (function trim(ws-feld1))
           =
            function upper-case
           (function trim(ws-feld2))
           then
              display " felder1-2/function identical"
           else
              display " felder1-2/function not identical"
           end-if
      * moving result of functions into field
           move function upper-case
           (function trim(ws-feld1))
           to ws-feld3
           
           move function upper-case
           (function trim(ws-feld2))
           to ws-feld4
      * Compare WS-Feld3/WS-Feld4
           if ws-feld3 = ws-feld4
           then
              display " felder3-4 identical"
           else
              display " felder3-4 not identical"
           end-if
      *

           stop run.

      *

This is the result:

<WERT1     >
<WERT1 X   >
<Wert1>
<wert1 x>
<WERT1>
<WERT1 X>
felder1-2 not identical
felder1-2/function identical
felder3-4 not identical

What I didn't expect is the result "felder1-2/function identical":

Any explanations for this behaviour?

Solution

  • Answer: your example program (I've edited the original snipped to a complete program and applied English translation) is fine, you found a bug in your COBOL compiler (likely related to how intermediate results of functions are cached) [I've verified that bug in VC7 and VC9].

    Testing the example program with GnuCOBOL and GCC-COBOL at https://cobol.godbolt.org/z/1noYo59cY resulted in all of the compiler versions with the expected

     felder1-2 not identical
 felder1-2/function not identical
 felder3-4 not identical

    which is also the result the ISO COBOL 2002+ standard would expect.

    Possible solutions: