with my OPTIONAL variable (sortz), retlog=present(sortz) not working

[kvrichardson]

With my OPTIONAL variable (sortz), retlog=present(sortz) and (present(sortz) aren't working.

Not sure why. Here's what I have:

SUBROUTINE LIBRARIAN(prompt,choices,nchoices,nchosen,opts,nopts,
+optchosen,sortz)
USE DFLOGM
IMPLICIT NONE
............
LOGICAL, OPTIONAL :: sortz
LOGICAL(KIND=4) retlog
INTEGER x
...........
retlog=present(sortz)
if (retlog) then
x=1
else
x=2
endif

if (present(sortz) then
x=1
else
x=2
endif

With either test, the result is always x=1 even when I know I haven't passed the optional variable and in debug you can see it as "undefined".

This is a mixed language project - would my settings for "C, by reference", "Uppercase" or for "After All Args" disturb the workings of this ?

Any ideas would be appreciated.

Keith Richardson

[kvrichardson]

cancel this...I just found part on optional in Dr. Fortran in latest (12/00) newsletter!!!!

Thanks, Steve!

[Steven_L_Intel1]

I'm glad to see that the Good Doctor was able to be of assistance.

Steve

[kvrichardson]

Now we're going to see why they call him 'THE GOOD DOCTOR' !

I read your piece and realized I either needed an interface in the calling routine or a contained subroutine. Since I have 50 calling routines, many of which include the optional sortz logical in the call, I opted for the former. So I changed my code to the following (changed or new lines as indicated):

SUBROUTINE LIBRARIAN(prompt,choices,nchoices,nchosen,opts,nopts,   
     + optchosen,sortz)   
USE DFLOGM   
IMPLICIT NONE   
NEW -*INCLUDE 'CPCOM.FOR'             !to use COMMON variable libsort  
INCLUDE 'RESOURCE.FD'   
CHARACTER*(*) prompt   
integer nchoices   
CHARACTER*(*) choices(nchoices)   
integer nchosen, nopts   
character*40 opts(nopts)   
integer optchosen   
changed-*LOGICAL sortz, sortz2           !removed OPTIONAL here, added sortz2  
INTEGER x   
INTEGER*4 retint, numc   
integer ln(nchoices)   
COMMON numc   
EXTERNAL DISCALL   
TYPE (dialog) dlg   
   
  
NEW -*libsort=.false. !default is sortz is not present  
NEW -*call TEST (sortz)    !sets libsort to .true. if sortz present, in contained subr. 			below  
NEW -*if (.not.libsort) then   
NEW -*	sortz2=.false.   !sortz not present so do not sort  
NEW -*else  
NEW -*	sortz2=sortz  
NEW -*endif  
  
	if (sortz2) then 			   !use sortz2 instead of sortz  
	!launch dialog with sorted list box   
	IF(.not. DlgInit(IDD_LIBRARIAN_SORTED_4_OPT, dlg)) THEN   
		WRITE (*,*) "ERROR: dialog not found"   
	ELSE   
		...............   
	ENDIF   
	else   
		....!launch dialog w/out sorted list box   
	endif   
	RETURN   
new-* CONTAINS   
new-* SUBROUTINE TEST(sortlog)  
new-*	include 'cp.com'  
new-* 	OPTIONAL :: sortlog   
new-* 	IF (PRESENT(sortlog)) libsort=.TRUE.   
new-* 	END SUBROUTINE TEST   
       END SUBROUTINE   

So, in prose, I added the CONTAINS SUBROUTINE TEST, removed the optional switch for sortz (actually, I tried it both ways and it didn't make a difference), and called to TEST.

In debugging, I stepped into TEST and libsort got set to .true. in the contained subroutine TEST whether or not sortz was present (whether it said "undefined address" in the debugger or was actually set to .true. or .false.).

Very strange. What am I not understanding?

Thanks doc,

Keith

[kvrichardson]

If my code is packed together in a giant run-on sentence when you folks read the prior post and you'd like to see it, just let me know and I'll e-mail it to you.

Keith

[Steven_L_Intel1]

In the code you've given, SORTZ is always going to be present, because it is specified in the call to TEST and is not OPTIONAL in LIBRARIAN. If you want to test whether SORTZ was passed in to LIBRARIAN, it has to be OPTIONAL here *AND* anyone who calls LIBRARIAN needs to have an explicit interface for it.

Steve (aka Dr. Fortran)

P.S. To prevent your code from running together, bracket it with:

 
...

I edited your entry to do that.

[kvrichardson]

Thanks. That explains it!