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From: murat@fir.ucsb.edu (Karaorman, Murat)
Newsgroups: comp.lang.eiffel
Subject: Re: C and Eiffel ? (A correction)
Message-ID: <12109@hub.ucsb.edu>
Date: 18 Jun 91 21:20:10 GMT
References: <702@mailgzrz.tu-berlin.de> <12051@hub.ucsb.edu>
Sender: news@hub.ucsb.edu
Reply-To: murat@cs.ucsb.edu (Murat Karaorman)
Organization: University of California, Santa Barbara
Lines: 70

In my previous posting, <12051@hub.ucsb.edu>, about calling Eiffel routines 
from C, I just noticed that I have overlooked an important (yet obvious) 
mistake that was in the original documentation. I had stated it in words:
 
>2.1) In this C program you shouldn't use eif_rout ( ... )  to invoke a 
>   method, but instead obtain a function pointer to the method and then
>   invoke the method via this pointer. You can look at the example I give.

but forgotten to include in the example.

Here the type of eif_rout() needs to be a function pointer, namely ROUT_PTR,
as opposed to the type DATUM in the original article, therefore the 
example program should read:

==============================test.c=======================================
  #include "/cad01/Eiffel/files/_eiffel.h"
  #include <stdio.h>

>> #include " ... rename.h "
>> #include " ... Eiffel_rout.h"

  extern OBJPTR eif_create ();
<<  extern DATUM    eif_rout();
>>  extern ROUT_PTR eif_rout ();
  extern int eif_attr ();

<<  int test ()
>>  main ()
  {
    OBJPTR obj;
>>  ROUT_PTR f_ptr;

>>  my_name_eiffel_init();
 
    obj = eif_create("string",(DATUM) 10);

>>  f_ptr = eif_rout (obj, "append");
>>  (* f_ptr)(obj, MakeStr("Hello world"));
 
<<  eif_rout(obj, "append", MakeStr("Hello world"));
    printf("Size of Eiffel string is: %d\n",(int32) eif_attr (obj, "size"));
    return 25;
  }

=================================end====================================

   The lines starting with >> are my insertions,
   The lines starting with << were in your original, they need to be removed,
   The rest is unchanged (except for inserting DATUM) from your original.
 
Sorry for any inconvenience this may have caused.

Murat Karaorman,

>
>I hope this helps. Let me know if anything goes wrong. It has been a while
>now, but I know that this stuff should eventually work.
>
>good luck,
>
>-----------------------------------------------------------------------------.
>|        Two men say they're Jesus...					      |
>|        One of them must be wrong.					      |
>|                     -Dire Straits "Industrial Disease" from Love Over Gold  |


------------ Two men say they're Jesus...    ----.
|             One of them must be wrong.	  |
|                             -Dire Straits       |
`----  murat@cs.ucsb.edu -------------------------'