[Info-vax] Error Messages in Basic - %BASIC-E-PARMODNOT, mode for parameter <n> of routine <procedure-name> not as declared

[Bob Gezelter]

On Saturday, June 8, 2019 at 2:21:45 PM UTC-4, Jeffrey H. Coffield wrote:
> On 06/05/2019 07:45 AM, DuncanMorris wrote:
> > On Wednesday, June 5, 2019 at 3:28:00 PM UTC+1, Jeffrey H. Coffield wrote:
> >> The following compiles and runs for me on both Alpha and Itanium. You
> >> must have something wrong in how you are declaring the function.
> >>
> >>           program test
> >>
> >>          external long function lib$convert_date_string
> >>
> >>          Declare Long            Date_Time_Context_gl
> >>          Declare String          End_of_Month_Date_gs
> >>          Declare Quad            End_of_Month_Date_Time_gq
> >>          Declare Long            End_of_Month_Weekday_gl
> >>          Declare Long            VMS_Condition_Code_gl
> >>
> >>          End_of_Month_Date_gs = '31-may-2019 01:23:45.67'
> >>
> >>          VMS_Condition_Code_gl   &
> >>                  = LIB$CONVERT_DATE_STRING (End_of_Month_Date_gs, &
> >>                  End_of_Month_Date_Time_gq, &
> >>                  Date_Time_Context_gl )
> >>
> >>          print VMS_Condition_Code_gl
> >>          print End_of_Month_Date_Time_gq
> >>
> >>          end
> >>
> >>
> >>
> >> On 06/05/2019 06:48 AM, Craig Dedo wrote:
> >>> VMS_Condition_Code_gl   = LIB$CONVERT_DATE_STRING ( End_of_Month_Date_gs, End_of_Month_Date_Time_gq, Date_Time_Context_gl )
> >
> > Nothing wrong, per se, with the program.
> >
> > As Hoff has pointed out, the external definition in the library expects BASIC$QUADWORD for parameter 2. This is not seen as the same type as QUAD.
> >
> > Try this-
> > program test
> >
> > %include "starlet"           %from %library   "sys$library:basic$starlet"      ! System Services declarations
> > %include "$ssdef"              %from %library   "sys$library:basic$starlet"      ! condition codes
> > %include "lib$routines"          %from %library   "sys$library:basic$starlet"      ! LIBRTL routines
> >
> >          Declare Long            Date_Time_Context_gl
> >          Declare String          End_of_Month_Date_gs
> >          Declare Quad            End_of_Month_Date_Time_gq
> >          Declare Long            End_of_Month_Weekday_gl
> >          Declare Long            VMS_Condition_Code_gl
> >
> >          End_of_Month_Date_gs = '31-may-2019 01:23:45.67'
> >
> >          VMS_Condition_Code_gl   &
> >                  = LIB$CONVERT_DATE_STRING (End_of_Month_Date_gs, &
> >                  End_of_Month_Date_Time_gq, &
> >                  Date_Time_Context_gl )
> >
> >          print VMS_Condition_Code_gl
> >          print End_of_Month_Date_Time_gq
> >
> >          end
> >
> > I1        12238     !     LIB$CONVERT_DATE_STRING
> > I1        12239     !
> > I1        12240     !     Convert Date String to Quadword
> > I1        12241     !
> > I1        12242     !     The Convert Date String to Quadword routine converts an absolute date
> > I1        12243     !     string into a VMS internal format date-time quadword. That is, given
> > I1        12244     !     an input date/time string of a specified format,
> > I1        12245     !     LIB$CONVERT_DATE_STRING converts this string to a VMS internal format
> > I1        12246     !     time.
> > I1        12247     !
> > I1        12248       EXTERNAL LONG FUNCTION  lib$convert_date_string &
> > I1        12249                ( &
> > I1        12250                    STRING  BY DESC, &
> > I1        12251                    BASIC$QUADWORD  BY REF, &
> > I1        12252                   OPTIONAL LONG  BY REF, &
> >
> 
> There are a number of places in both text libraries as well as .BAS 
> files that have the following "patch":
> 
>        %IF %DECLARED(%BASIC$QUADWORD_DECLARED) = 0 %THEN
>           RECORD BASIC$QUADWORD
>              LONG FILL(2)
>           END RECORD
>           %LET %BASIC$QUADWORD_DECLARED = 1
>        %END %IF
> 
> because Basic didn't have a quad data type. It does now and this 
> could/should be cleaned up.
> 
> There are other long time errors and omissions in Basic support that I 
> have had to keep my own fixed/stable versions of some of the library 
> files so my programs will work. Notably the files concerning XAB 
> structures for Basic would change/break with new versions of OpenVMS.
> 
> If anyone is interested in fixing, I can dig up some small samples.
> 
> Also, if there is a list of things to do, Basic still does not support a 
> get/find key "LT" or "LE" which RMS supports.

Jeffrey,

At first glance, when I encountered this I agreed. However, on detailed consideration, the problem is more complex.

Changing the BASIC$QUADWORD definition to a simple quadword would invalidate all existing code. It would be a nasty incompatibility, causing a lot of rework to existing code.

One could do something with conditional code, but it would be complex to implement and document. 

Hoff has referred to this type of problem using words along the line of "curse of compatibility". I am forced to agree. The solution (using a struct) made sense when done, but events have made the existing solution awkward and dated. Changing the solution breaks existing code.

- Bob Gezelter, http://www.rlgsc.com