Groups | Search | Server Info | Login | Register


Groups > comp.lang.forth > #23593

Re: C interface

From anton@mips.complang.tuwien.ac.at (Anton Ertl)
Newsgroups comp.lang.forth
Subject Re: C interface
Date 2013-06-14 12:51 +0000
Organization Institut fuer Computersprachen, Technische Universitaet Wien
Message-ID <2013Jun14.145121@mips.complang.tuwien.ac.at> (permalink)
References (6 earlier) <_MmdnWPnRPVw2CzMnZ2dnUVZ_vadnZ2d@supernews.com> <2013Jun11.174104@mips.complang.tuwien.ac.at> <jvGdnWyR26uR7yXMnZ2dnUVZ_j2XnZ2d@supernews.com> <2013Jun12.163859@mips.complang.tuwien.ac.at> <6fmdnQYWQ6kfICXMnZ2dnUVZ_iydnZ2d@supernews.com>

Show all headers | View raw


Andrew Haley <andrew29@littlepinkcloud.invalid> writes:
>Anton Ertl <anton@mips.complang.tuwien.ac.at> wrote:
>> Andrew Haley <andrew29@littlepinkcloud.invalid> writes:
>>>Anton Ertl <anton@mips.complang.tuwien.ac.at> wrote:
>>>> An instructive example is lseek().  It returns an off_t (which is not
>>>> represented in the object code),
>>>
>>>In what sense is it not represented?
>> 
>> readelf -Ws libc.so.6 |grep off_t
>> 
>> gives no output.
>
>Why should it?  It's a numeric type.

As I said, it's not represented in the object code.

Why should it?  Well, maybe it shouldn't, but then you should not base
a foreign language interface on object code.  Object code just does
not contain enough information.

>>>How could it possibly be represented?
>> 
>> It's represented in the source code:
>> 
>> gcc -E /usr/include/sys/types.h|grep off_t
>> 
>> gives
>> 
>> typedef long int __off_t;
>> typedef __off64_t __loff_t;
>> typedef __loff_t loff_t;
>> typedef __off_t off_t;
>
>So it's a long.  I still don't see what the problem is.

On this particular system when compiled with the default flags its a
long.  On another system it's something else.  There is no way for the
foreign language interface to get the knowledge of the return type of
lseek() from libffi, because libffi just looks at object code, and that
kind of information is not there.

>> how do I look up the value of SEEK_SET with libffi?
>
>You can't.  That's not what libffi is for.  You might as well ask why
>your vacuum cleaner can't make toast.

Yes.  Your question actually was why libffi does not work well as a C
interface, and you answered it yourself.

- anton
-- 
M. Anton Ertl  http://www.complang.tuwien.ac.at/anton/home.html
comp.lang.forth FAQs: http://www.complang.tuwien.ac.at/forth/faq/toc.html
     New standard: http://www.forth200x.org/forth200x.html
   EuroForth 2013: http://www.euroforth.org/ef13/

Back to comp.lang.forth | Previous | NextPrevious in thread | Next in thread | Find similar


Thread

On the importance of standards Joshua Litt <jalitt@gmail.com> - 2013-06-03 22:42 -0700
  Re: On the importance of standards Steve <nospam275@gmail.com> - 2013-06-03 23:59 -0700
    Re: On the importance of standards Alex McDonald <blog@rivadpm.com> - 2013-06-04 06:16 -0700
      Re: On the importance of standards Steve <nospam275@gmail.com> - 2013-06-10 20:51 +1000
        Re: On the importance of standards Alex McDonald <blog@rivadpm.com> - 2013-06-11 22:03 -0700
          Re: On the importance of standards Paul Rubin <no.email@nospam.invalid> - 2013-06-11 22:32 -0700
            Re: On the importance of standards Alex McDonald <blog@rivadpm.com> - 2013-06-12 13:06 -0700
              Re: On the importance of standards Steve <nospam275@gmail.com> - 2013-06-13 22:34 +1000
              Re: On the importance of standards rickman <gnuarm@gmail.com> - 2013-06-14 19:09 -0400
                Re: On the importance of standards Steve <nospam275@gmail.com> - 2013-06-23 19:02 +1000
                Re: On the importance of standards rickman <gnuarm@gmail.com> - 2013-06-23 13:55 -0400
            Re: On the importance of standards Steve <nospam275@gmail.com> - 2013-06-13 22:08 +1000
          Re: On the importance of standards Steve <nospam275@gmail.com> - 2013-06-13 23:28 +1000
            Re: On the importance of standards Mark Wills <markrobertwills@yahoo.co.uk> - 2013-06-13 07:41 -0700
              Re: On the importance of standards Steve <nospam275@gmail.com> - 2013-06-23 19:06 +1000
            Re: On the importance of standards Brad Eckert <hwfwguy@gmail.com> - 2013-06-13 10:10 -0700
              Re: On the importance of standards Steve <nospam275@gmail.com> - 2013-06-23 19:19 +1000
            Re: On the importance of standards Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-06-13 12:33 -0500
              Re: On the importance of standards Steve <nospam275@gmail.com> - 2013-06-23 19:28 +1000
                Re: On the importance of standards Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-06-23 11:58 -0500
                Re: On the importance of standards "Alex McDonald" <blog@rivadpm.com> - 2013-06-25 20:00 +0100
            Re: On the importance of standards "Elizabeth D. Rather" <erather@forth.com> - 2013-06-13 07:55 -1000
              Re: On the importance of standards Alex McDonald <blog@rivadpm.com> - 2013-06-13 12:35 -0700
                Re: On the importance of standards Bernd Paysan <bernd.paysan@gmx.de> - 2013-06-13 23:18 +0200
                Re: On the importance of standards Steve <nospam275@gmail.com> - 2013-06-23 19:41 +1000
              Re: On the importance of standards Steve <nospam275@gmail.com> - 2013-06-23 19:37 +1000
            Re: On the importance of standards Alex McDonald <blog@rivadpm.com> - 2013-06-13 12:00 -0700
              Re: On the importance of standards Steve <nospam275@gmail.com> - 2013-06-23 21:41 +1000
                Re: On the importance of standards "Alex McDonald" <blog@rivadpm.com> - 2013-06-25 20:08 +0100
            Re: On the importance of standards rickman <gnuarm@gmail.com> - 2013-06-14 19:16 -0400
              Re: On the importance of standards Steve <nospam275@gmail.com> - 2013-06-23 20:33 +1000
  Re: On the importance of standards Elizabeth D Rather <erather@forth.com> - 2013-06-03 21:32 -1000
    Re: On the importance of standards Steve <nospam275@gmail.com> - 2013-06-04 01:33 -0700
    Re: On the importance of standards Paul Rubin <no.email@nospam.invalid> - 2013-06-04 01:36 -0700
      Re: On the importance of standards albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-06-04 10:14 +0000
      Re: On the importance of standards Alex McDonald <blog@rivadpm.com> - 2013-06-04 05:51 -0700
  Re: On the importance of standards Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-06-04 05:46 -0500
    Re: On the importance of standards Steve <nospam275@gmail.com> - 2013-06-06 11:13 -0700
      Re: On the importance of standards rickman <gnuarm@gmail.com> - 2013-06-06 16:47 -0400
      Re: On the importance of standards Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-06-06 21:29 -0500
        Re: On the importance of standards Steve <nospam275@gmail.com> - 2013-06-08 04:26 +1000
  Re: On the importance of standards anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-06-04 12:03 +0000
  Re: On the importance of standards Alex McDonald <blog@rivadpm.com> - 2013-06-04 06:00 -0700
    Re: On the importance of standards anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-06-04 13:20 +0000
      Re: On the importance of standards Alex McDonald <blog@rivadpm.com> - 2013-06-04 06:33 -0700
        Re: On the importance of standards anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-06-04 13:40 +0000
          Re: On the importance of standards Alex McDonald <blog@rivadpm.com> - 2013-06-04 07:42 -0700
            Re: On the importance of standards Lars Brinkhoff <lars.spam@nocrew.org> - 2013-06-04 18:02 +0200
              Re: On the importance of standards Alex McDonald <blog@rivadpm.com> - 2013-06-04 09:07 -0700
                Re: On the importance of standards Lars Brinkhoff <lars.spam@nocrew.org> - 2013-06-04 19:16 +0200
                Re: On the importance of standards rickman <gnuarm@gmail.com> - 2013-06-04 14:27 -0400
                TRAVERSE-WORDLIST (was Re: On the importance of standards) Alex McDonald <blog@rivadpm.com> - 2013-06-13 15:55 -0700
                Re: TRAVERSE-WORDLIST Lars Brinkhoff <lars.spam@nocrew.org> - 2013-06-14 13:39 +0200
                Re: TRAVERSE-WORDLIST Alex McDonald <blog@rivadpm.com> - 2013-06-14 09:06 -0700
                Re: TRAVERSE-WORDLIST anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-06-17 17:05 +0000
                Re: TRAVERSE-WORDLIST Alex McDonald <blog@rivadpm.com> - 2013-06-17 21:29 -0700
  Re: On the importance of standards stephenXXX@mpeforth.com (Stephen Pelc) - 2013-06-04 13:51 +0000
    Re: On the importance of standards Bernd Paysan <bernd.paysan@gmx.de> - 2013-06-05 01:24 +0200
      Re: On the importance of standards stephenXXX@mpeforth.com (Stephen Pelc) - 2013-06-05 09:25 +0000
        Re: On the importance of standards m.a.m.hendrix@tue.nl - 2013-06-05 04:31 -0700
          Re: On the importance of standards Alex McDonald <blog@rivadpm.com> - 2013-06-05 05:41 -0700
            Re: On the importance of standards mhx@iae.nl (Marcel Hendrix) - 2013-06-05 21:16 +0200
              Re: On the importance of standards Alex McDonald <blog@rivadpm.com> - 2013-06-05 12:41 -0700
          Re: On the importance of standards stephenXXX@mpeforth.com (Stephen Pelc) - 2013-06-05 12:53 +0000
            Re: On the importance of standards Bernd Paysan <bernd.paysan@gmx.de> - 2013-06-06 04:20 +0200
              Re: On the importance of standards m.a.m.hendrix@tue.nl - 2013-06-06 00:06 -0700
                Re: On the importance of standards Bernd Paysan <bernd.paysan@gmx.de> - 2013-06-06 15:32 +0200
                Re: On the importance of standards mhx@iae.nl (Marcel Hendrix) - 2013-06-06 17:09 +0200
                Re: On the importance of standards Bernd Paysan <bernd.paysan@gmx.de> - 2013-06-06 22:44 +0200
                Re: On the importance of standards Roelf Toxopeus <rt4all@notthis.hetnet.nl> - 2013-06-07 10:16 +0200
              Re: On the importance of standards Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-06-06 21:31 -0500
                Re: On the importance of standards Bernd Paysan <bernd.paysan@gmx.de> - 2013-06-08 00:58 +0200
                Re: On the importance of standards Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-06-07 22:02 -0500
                Re: On the importance of standards Bernd Paysan <bernd.paysan@gmx.de> - 2013-06-09 00:55 +0200
                C interface (was: On the importance of standards) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-06-11 15:41 +0000
                Re: C interface (was: On the importance of standards) Bernd Paysan <bernd.paysan@gmx.de> - 2013-06-11 18:45 +0200
                Re: C interface Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-06-12 08:05 -0500
                Re: C interface anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-06-12 14:38 +0000
                Re: C interface Bernd Paysan <bernd.paysan@gmx.de> - 2013-06-12 20:15 +0200
                Re: C interface Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-06-14 22:52 -0500
                Re: C interface Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-06-12 13:27 -0500
                Re: C interface anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-06-14 12:51 +0000
                Re: C interface Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-06-14 22:47 -0500
                Re: C interface anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-06-17 16:44 +0000
                Re: C interface Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-06-17 12:46 -0500
                Re: C interface anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-06-18 07:23 +0000
                Re: C interface Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-06-18 04:06 -0500
                Re: C interface m.a.m.hendrix@tue.nl - 2013-06-18 03:51 -0700
                Re: C interface anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-06-18 16:10 +0000
                Re: C interface Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-06-18 13:24 -0500
          Foreign language interface (was: On the importance of standards) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-06-05 15:35 +0000
            Re: Foreign language interface (was: On the importance of standards) stephenXXX@mpeforth.com (Stephen Pelc) - 2013-06-05 17:37 +0000
              Re: Foreign language interface (was: On the importance of standards) Bernd Paysan <bernd.paysan@gmx.de> - 2013-06-06 04:28 +0200
              Re: Foreign language interface (was: On the importance of standards) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-06-14 15:23 +0000
                Re: Foreign language interface (was: On the importance of standards) Bernd Paysan <bernd.paysan@gmx.de> - 2013-06-15 14:33 +0200
            Re: Foreign language interface (was: On the importance of standards) mhx@iae.nl (Marcel Hendrix) - 2013-06-05 21:32 +0200
              Re: Foreign language interface (was: On the importance of standards) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-06-14 15:05 +0000
                Re: Foreign language interface (was: On the importance of standards) mhx@iae.nl (Marcel Hendrix) - 2013-06-14 21:42 +0200
                Re: Foreign language interface (was: On the importance of standards) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-06-17 16:53 +0000
            Re: Foreign language interface (was: On the importance of standards) Spam@ControlQ.com - 2013-06-05 16:01 -0400
              Re: Foreign language interface (was: On the importance of  standards) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-06-14 14:55 +0000
                Re: Foreign language interface (was: On the importance of  standards) Spam@ControlQ.com - 2013-06-14 15:28 -0400
        Re: On the importance of standards Bernd Paysan <bernd.paysan@gmx.de> - 2013-06-06 04:14 +0200
      Re: On the importance of standards glidedog@gmail.com - 2013-06-23 02:55 -0700
    Re: On the importance of standards Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-06-06 15:25 -0500
  Re: On the importance of standards "Rod Pemberton" <do_not_have@notemailnotq.cpm> - 2013-06-04 17:48 -0400
    Re: On the importance of standards visualforth@rocketmail.com - 2013-06-04 15:06 -0700
    Re: On the importance of standards visualforth@rocketmail.com - 2013-06-04 15:40 -0700
    Re: On the importance of standards Lars Brinkhoff <lars.spam@nocrew.org> - 2013-06-05 07:30 +0200
    Re: On the importance of standards Steve <nospam275@gmail.com> - 2013-06-08 04:33 +1000
  Re: On the importance of standards Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-06-05 02:09 +0000
    Re: On the importance of standards Paul Rubin <no.email@nospam.invalid> - 2013-06-04 19:32 -0700
      Re: On the importance of standards Doug Hoffman <glidedog@gmail.com> - 2013-06-05 00:06 -0400
    Re: On the importance of standards rickman <gnuarm@gmail.com> - 2013-06-04 22:50 -0400
    Re: On the importance of standards "Elizabeth D. Rather" <erather@forth.com> - 2013-06-04 19:02 -1000
      Re: On the importance of standards Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-06-05 23:16 +0000
        Re: On the importance of standards Elizabeth D Rather <erather@forth.com> - 2013-06-05 13:43 -1000
          Re: On the importance of standards "Ed" <invalid@invalid.com> - 2013-06-06 11:14 +1000
            Re: On the importance of standards Elizabeth D Rather <erather@forth.com> - 2013-06-05 15:27 -1000
              Re: On the importance of standards "Ed" <invalid@invalid.com> - 2013-06-06 15:28 +1000
  Re: On the importance of standards Paul Rubin <no.email@nospam.invalid> - 2013-06-05 00:03 -0700
  Re: On the importance of standards Joshua Litt <jalitt@gmail.com> - 2013-06-06 17:15 -0700
    Re: On the importance of standards "Elizabeth D. Rather" <erather@forth.com> - 2013-06-06 14:45 -1000
      Re: On the importance of standards Joshua Litt <jalitt@gmail.com> - 2013-06-06 19:24 -0700
        Re: On the importance of standards Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-06-06 21:38 -0500
          Re: On the importance of standards Joshua Litt <jalitt@gmail.com> - 2013-06-07 14:39 -0700
            Re: On the importance of standards Steve <nospam275@gmail.com> - 2013-06-09 00:57 +1000
              Re: On the importance of standards Paul Rubin <no.email@nospam.invalid> - 2013-06-08 10:44 -0700
                Re: On the importance of standards Steve <nospam275@gmail.com> - 2013-06-09 06:11 +1000
                Re: On the importance of standards Paul Rubin <no.email@nospam.invalid> - 2013-06-08 14:47 -0700
                Re: On the importance of standards Steve <nospam275@gmail.com> - 2013-06-10 00:03 +1000
                Re: On the importance of standards rickman <gnuarm@gmail.com> - 2013-06-09 15:00 -0400
                Re: On the importance of standards Paul Rubin <no.email@nospam.invalid> - 2013-06-09 12:26 -0700
                Re: On the importance of standards rickman <gnuarm@gmail.com> - 2013-06-09 15:41 -0400
                Re: On the importance of standards Paul Rubin <no.email@nospam.invalid> - 2013-06-09 13:11 -0700
                Re: On the importance of standards Paul Rubin <no.email@nospam.invalid> - 2013-06-09 13:14 -0700
                Re: On the importance of standards Steve <nospam275@gmail.com> - 2013-06-10 18:41 +1000
                Re: On the importance of standards rickman <gnuarm@gmail.com> - 2013-06-09 17:09 -0400
                Re: On the importance of standards Steve <nospam275@gmail.com> - 2013-06-10 18:35 +1000
                Re: On the importance of standards Bernd Paysan <bernd.paysan@gmx.de> - 2013-06-10 16:04 +0200
                Re: On the importance of standards Paul Rubin <no.email@nospam.invalid> - 2013-06-15 01:08 -0700
                Re: On the importance of standards Steve <nospam275@gmail.com> - 2013-06-10 20:13 +1000
                Re: On the importance of standards rickman <gnuarm@gmail.com> - 2013-06-10 11:35 -0400
                Re: On the importance of standards Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-06-10 17:37 -0500
                Re: On the importance of standards rickman <gnuarm@gmail.com> - 2013-06-10 18:46 -0400
                Re: On the importance of standards Paul Rubin <no.email@nospam.invalid> - 2013-06-10 16:36 -0700
                Re: On the importance of standards rickman <gnuarm@gmail.com> - 2013-06-10 20:09 -0400
                Re: On the importance of standards Steve <nospam275@gmail.com> - 2013-06-13 21:55 +1000
                Re: On the importance of standards Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-06-11 09:56 -0500
                Re: On the importance of standards Bernd Paysan <bernd.paysan@gmx.de> - 2013-06-11 18:40 +0200
                Re: On the importance of standards rickman <gnuarm@gmail.com> - 2013-06-11 22:36 -0400
                Re: On the importance of standards Bernd Paysan <bernd.paysan@gmx.de> - 2013-06-15 14:30 +0200
                Re: On the importance of standards rickman <gnuarm@gmail.com> - 2013-06-15 19:20 -0400
                Re: On the importance of standards Bernd Paysan <bernd.paysan@gmx.de> - 2013-06-16 22:37 +0200
                Re: On the importance of standards Steve <nospam275@gmail.com> - 2013-06-23 17:14 +1000
                Re: On the importance of standards Steve <nospam275@gmail.com> - 2013-06-13 21:33 +1000
                Re: On the importance of standards rickman <gnuarm@gmail.com> - 2013-06-15 13:21 -0400
                Re: On the importance of standards Steve <nospam275@gmail.com> - 2013-06-23 18:58 +1000
                Re: On the importance of standards rickman <gnuarm@gmail.com> - 2013-06-08 18:42 -0400
                Re: On the importance of standards Steve <nospam275@gmail.com> - 2013-06-09 23:27 +1000
                Re: On the importance of standards "WJ" <w_a_x_man@yahoo.com> - 2013-06-10 16:11 +0000
    Re: On the importance of standards Steve <nospam275@gmail.com> - 2013-06-08 05:11 +1000

csiph-web