Re: [open-cobol-list] nested call statements, best practices

[Michael Anderson]

There is a cobc directive for that.
-fnull-param          Pass extra NULL terminating pointers on CALL 
statements

OR, What I do for this situation:

Working Storage.
 1 astring pic x(32000).
 1 bstring pic x(24) value "       asdfgh           ".

Procedure Division.
 begin.
        String trim(bstring) X"00" Delimited by size into astring.

NOTE: MOVE pads with trailing spaces, where STRING does not!
After the above "STRING" statement, 'astring' contains 'asdfgh' followed 
by a single null byte, followed by 31k bytes of "Who the heck knows".
But the remainder 31k bytes does not matter in C, because when you pass 
it to C everything after the NULL is ignored, but you could initialize 
it to something.
Something like LOW-VALUES, which is all NULLS, in which case you could just:

        Move Low-Values To astring.
        String trim(bstring) Delimited by size into astring.

Now 'astring' contains 'asdfgh' followed by a 31k null bytes, if you had 
used MOVE instead, you'd have 'asdfgh' followed 31k of spaces.
Using STRING, not MOVE, and Passing astring to a C function, the C 
function see's only 'asdfgh', but the C function should allow space for 
at least one null character at the end.

Maybe Brian could write an example of a OpenCobol 2.0 function to do 
this, but it would require OpenCobol 2.0,
I'd like to see what 2.0 functions look like.




On 09/17/2013 12:27 PM, Patrick wrote:
> Thanks Michael
>
> I was thinking about reposting, there was missing information I should 
> have included and the mailing list reformatted my code so it was 
> really hard to read.
>
> Here is what I am trying to do in non-Cobol-ish pseudo code
>
> Example 1:
>
> cFunction = would be a call statement calling cFunction
> cob-str-to-C = a utility to trim strings and append nul byte
> incompatible = a picture based Cobol string
>
> cFunction ( cob-str-to-C ( incompatible ) )
>
>
>
> I know I could do something like
>
>
> Example 2
>
> temp = cob-str-to-C ( incompatible )
>
> CFunction ( temp )
>
> But then I have to use Cobol storage for the output of cob-str-to-C 
> and that might be an issue. i was thinking that a nested call result 
> would not have to be passed back into the PICTURE based system..
>
> Does this make any more sense? Sorry to everyone for the last post.
>
> Thanks