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RE: [open-cobol-list] PROGRAM-ID, source name and entry points


From: Bill Klein
Subject: RE: [open-cobol-list] PROGRAM-ID, source name and entry points
Date: Mon Jan 30 14:13:02 2006

Let's ignore (for the moment)
 - Alphanumeric (or national) literals in Program-ID (extension)
 - ENTRY statement (extension)
 - AS phrase in Program-ID ('02 Standard)
 - Call prototypes ('02 Standard)

The question of "upper-/lower-case" equivalence in program-names with the
'85 Standard was dealt with in an "interpretation request".  The answer (If
you need the CIB number, I'll look it up for you) was that BOTH the
program-name in the Program-Id paragraph and the identifier (*OR LITERAL*)
in the CALL statement are "COBOL words" - therefore, case MUST not be
considered in resolving CALL statements.

When ANSI/(ISO) determined this, was when Micro Focus added the CASE and
FOLD-CALL-NAME directives.  (Read the documentation for the SLIGHT
differences between the two directives).

 ***

Now when it comes to the ENTRY statement directive, there are other issues
that apply for "finding" the first call to a program (via an ENTRY
statement).  You should read the section

 "Entry Point Mapping for COBOL and Assembler Programs"

in the Mainframe Express User Guide.  (This talks about an "external file"
that one can create to allow for CALLs to ENTRY statements - without initial
calls to the "main" program-ID.  This corresponds (roughly) to what happens
in the IBM mainframe Linkage-Editor and/or Binder.

> -----Original Message-----
> From: address@hidden 
> [mailto:address@hidden On 
> Behalf Of Roger While
> Sent: Monday, January 30, 2006 7:18 AM
> To: Sergey Kashyrin
> Cc: address@hidden
> Subject: Re: [open-cobol-list] PROGRAM-ID, source name and 
> entry points
> 
> Sergey,
> The renaming is rather interesting. I did not realize the implications
> here. For MF, this only applies when creating ".int" or ".gnt" modules
> as presumably, they carry extra info. It does not work when creating
> ".so" modules (cob -z, for MF SE, not available for Object Cobol)
> 
> IF we would want to support your "CALL 'D'" scenario, how would we
> specify the "default" entry to the runtime?
> 
> Yes, of course, when a module is actually loaded, all it's 
> entry points
> become known.
> 
> (Incidentally, have implemented COB_PRE_LOAD environment variable;
>   more when I post CVS update notification).
> 
> Roger
> 
> >Roger,
> >
> >>Question is what, if anything, should we be doing here ?
> >
> >I don't think it's critical if we should do anything at all, 
> but that what 
> >MFocus is doing:
> >At the compile time if P-ID != surce file name (all converted to 
> >uppercase), it inserts both names in export list.
> >In runtime, it's looking for the filename of the CALL 
> statement (.gnt or 
> >.dll or ... depending on platform) and than it's looking for 
> the entry 
> >point with the same name.
> >If it  doesn't find it, it calls the first one (ignoring the 
> name at all).
> >After that ALL the names of this module became known for runtime.
> >i.e. I'm compiling program A.cbl with program id B and 
> additional entry C.
> >I'm renaming the resulting A.dll into D.dll.
> >Than I'm doing CALL "D" from the main program.
> >After that, the entry points A,B,C and D will be known for 
> runtime so the 
> >subsequent CALLs to A,B and D will call the same primary 
> entry of the 
> >program and CALL "C" will call additional entry point.
> >You can't compile the program which has ENTRY with the name 
> of source file.
> >
> >Regards,
> >Sergey
> >
> >----- Original Message ----- From: "Roger While" <address@hidden>
> >To: <address@hidden>
> >Cc: <address@hidden>
> >Sent: Sunday, January 29, 2006 3:15 AM
> >Subject: [open-cobol-list] PROGRAM-ID, source name and entry points
> >
> >
> >>When calling a program for the first time either
> >>explicitly with "CALL" or implicitly with a driver
> >>program (MF - cobrun, ACU - runcbl, OC - cobcrun),
> >>the runtime system tries to locate a loadable module
> >>with this name plus an extension (MF - .so, .int, .gnt;
> >>ACU - .out; OC .so).
> >>The runtime system then tries to locate an entry point
> >>within this module with the respective name.
> >>The default entry point of a program is the PROGRAM-ID
> >>(After accounting for AS clause, numeric first character,
> >>  non-printable characters, etc).
> >>
> >>Let's consider an actual example from the Cobol85 test
> >>suite - NC127A.CBL
> >>This is a program that is all lower case except for
> >>required literals. This includes the PROGRAM-ID
> >>which is nc127A.
> >>(Hmm, Why isn't the 'A' lower case ?)
> >>
> >>What MF and ACU (per default options) do is to fold
> >>the PROGRAM-ID to upper case.
> >>(Which is not what the MF SE doc says!)
> >>And therefore module name = entry point.
> >>
> >>OC does not do this so that attempting a
> >>"cobcrun NC127A" leads to "entry not found".
> >>
> >>Question is what, if anything, should we be
> >>doing here ?
> >>
> >>One possibility would be to insert the module
> >>name as an entry point if != P-ID and != ENTRY.
> >>Another would be to (optionally) fold the P-ID.
> >>
> >>Note we could have a completely different P-ID/ENTRY,
> >>eg in the OC tests where we have a "callee" program with
> >>P-ID "hello" and an ENTRY "bye".
> >>
> >>Thoughts ?
> >>
> >>Roger
> 
> 
> 
> 
> 
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