Re: compiling [old] c code

From	Ben Bacarisse <ben.usenet@bsb.me.uk>
Newsgroups	comp.lang.c
Subject	Re: compiling [old] c code
Date	2019-01-22 22:45 +0000
Organization	A noiseless patient Spider
Message-ID	<875zugz4yy.fsf@bsb.me.uk> (permalink)
References	(4 earlier) <f6946512-fc7d-44d1-bcf7-68e7780b4898@googlegroups.com> <877eex273c.fsf@bsb.me.uk> <048927d3-9039-4cce-84a2-1eec71d65eb5@googlegroups.com> <87fttkzllq.fsf@bsb.me.uk> <53d95acc-3eb2-4bee-9b44-6c4a2fd638f3@googlegroups.com>

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fir <profesor.fir@gmail.com> writes:

> W dniu wtorek, 22 stycznia 2019 17:46:35 UTC+1 użytkownik Ben Bacarisse napisał:
>> fir <profesor.fir@gmail.com> writes:
>> 
>> > W dniu poniedziałek, 21 stycznia 2019 19:34:08 UTC+1 użytkownik Ben Bacarisse napisał:
<snip>
>> >> Apart form the "big union" idea that's already been mentioned, you coud
>> >> try a macro:
>> >> 
>> >> #define PTR(p, s) ((struct s *)(p))
>> >> 
>> >> and re-write things like
>> >> 
>> >>   ttype = t->vtype;
>> >> 
>> >> as
>> >> 
>> >>   ttype = PTR(t, varblock)->vtype;
>> >> 
>> >> You might even be able to automate this a bit by using something like
>> >> Perl to record what structs have what members.
>> >
>> > it seems to me that he dont need to rewrite field acceses only
>> > maybe put
>> >
>> > ptr = (struct some*) ptr; //?
>> >
>> > in thet few places
>> 
>> This would be a constraint violation and yet would achieve nothing.
>> 
> what do you mean? you cant cast pointer
> on another type of pointer?

ptr is of type int *.  Assigning a struct some * to an int * object is
an error.  C, however, does not really have errors -- it has situations
that compiler must report.  These are called constraint violations and
your assignment is an example of one.

Your suggestion does not achieve anything because it does not solve the
problem.  You can't access the struct member after the assignment any
more that you could before.

-- 
Ben.

Thread

compiling all c code fiziqs@gmail.com - 2019-01-20 14:51 -0800
  Re: compiling all c code Richard Damon <Richard@Damon-Family.org> - 2019-01-20 18:41 -0500
  Re: compiling all c code gazelle@shell.xmission.com (Kenny McCormack) - 2019-01-20 23:42 +0000
  Re: compiling all c code Geoff <geoff@invalid.invalid> - 2019-01-20 16:44 -0800
    Re: compiling all c code fiziqs@gmail.com - 2019-01-21 02:36 -0800
      Re: compiling [old] c code Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-01-21 12:20 +0000
        Re: compiling [old] c code fiziqs@gmail.com - 2019-01-21 04:58 -0800
          Re: compiling [old] c code Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-01-21 18:33 +0000
            Re: compiling [old] c code fir <profesor.fir@gmail.com> - 2019-01-22 04:21 -0800
              Re: compiling [old] c code Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-01-22 16:46 +0000
                Re: compiling [old] c code fir <profesor.fir@gmail.com> - 2019-01-22 10:35 -0800
                Re: compiling [old] c code Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-01-22 22:45 +0000
                Re: compiling [old] c code fir <profesor.fir@gmail.com> - 2019-01-22 14:58 -0800
                Re: compiling [old] c code Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-01-23 02:12 +0000
                Re: compiling [old] c code fir <profesor.fir@gmail.com> - 2019-01-23 00:59 -0800
        Re: compiling [old] c code fir <profesor.fir@gmail.com> - 2019-01-22 03:34 -0800
          Re: compiling [old] c code fir <profesor.fir@gmail.com> - 2019-01-22 04:08 -0800
      Re: compiling all c code Keith Thompson <kst-u@mib.org> - 2019-01-21 14:23 -0800

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