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Re: [open-cobol-list] Re: feature request: implementation "IS EXTERNAL"
Re: [open-cobol-list] Re: feature request: implementation "IS EXTERNAL" (semantics)
Thu Dec 4 16:04:08 2003
On Friday 14 November 2003 12:40, Keisuke Nishida wrote:
> At Tue, 11 Nov 2003 17:17:31 +0100,
> Thomas Biehler wrote:
> > i have tested it with no success.
> Gee, I misunderstood the effect of EXTERNAL. What I did is to
> declare the field as an external variable in C. The field is
> not actually defined, so the undefined reference error happened.
> It seems a field with EXTERNAL should have both a declaration
> and a definition. How can I implement this? In C, there must
> be only one definition even if you compiled several modules.
> Hmm, maybe we need to generate a special module for external
> variables, or we need to resolve the field at run time.
I have a found a simple solution.
A BIG surprise for me!
It is NOT far away from the current trial!
To say it short: (the components of the solution which improve your trial)
1. the ANSI C 89 "tentative definition" for the "EXTERNAL GROUP-FIELD"
(the key "feature"; have a look on my comments in the c-sources!)
2. no initialization of the data members of the "EXTERNAL GROUP-FIELD"
(at least NO initializiation in a "subprogram")
3. a (unsigned char *) cast to make the C-Compiler quiet ;-)
To demonstrate the solution,
i have attached a uncompressed tar-Archive (40 KB) which contains:
in the subdir "externalpatch" :
- two Cobol-mainprograms: EXTERNALBUG.cob and EXTERNALBUG2.cob
- two Cobol-subprograms: UPROG.cob and UPROG2.cob
- the patched "cobc -save-temps ..." output from the compiliation
from the previous COBOL-program (*.c, *.c.h)
==> the "solution" and explaining comments are in that versions
in the topdir:
- a unified patch: is_external.patch
You can get the original (unpatched) output from the
"cobc -save-temps ..." invocation with
patch -p1 -R < ../is_external.patch
in the (copied) "externalpatch"-directory
Could you please implement it "soon" ? ;-)
It's easy, isn't it ?
Description: Unix tar archive
- Re: [open-cobol-list] Re: feature request: implementation "IS EXTERNAL" (semantics),
Thomas Biehler <=