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Re: Passing an integer to a function that accepts a void pointer

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On 05/12/11 08:59 PM, Heikki Kallasjoki wrote:
> On 2011-05-12, Ian Collins<ian-news@hotmail.com>  wrote:
>> On 05/12/11 07:56 PM, Columbus sailed the ocean China Blue wrote:
>>> Then you haven't seen any libraries that pass through a callerData to
>>> a callback function. These libraries advertise that can be a data
>>> pointer or small enough integer. Or unix signal interface. Or Tcl
>>> file handle interface.
>>
>> Well I've seen plenty and none of them made that claim.  They either
>> take an integer (signal callbacks) or a (typically void*) pointer.
>> Anything else is a hack.
>
> The POSIX signal interface accepts the user-provided "signal value"
> (when sending signals with sigqueue(2)) as an integer-pointer union,
>
> union sigval {
>    int sival_int;
>    void *sival_ptr;
> };
>
> Sending such union values around is of course a safe way to pass either
> a pointer or an integer.  (Assuming the handler knows which type of
> value to expect.)

Exactly the point, it uses a union to make the process safe.

-- 
Ian Collins

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Passing an integer to a function that accepts a void pointer pozz <pozzugno@gmail.com> - 2011-05-11 03:01 -0700
  Re: Passing an integer to a function that accepts a void pointer Tom St Denis <tom@iahu.ca> - 2011-05-11 03:52 -0700
    Re: Passing an integer to a function that accepts a void pointer pete <pfiland@mindspring.com> - 2011-05-11 08:10 -0400
    Re: Passing an integer to a function that accepts a void pointer pozz <pozzugno@gmail.com> - 2011-05-11 18:28 +0200
      Re: Passing an integer to a function that accepts a void pointer Shao Miller <sha0.miller@gmail.com> - 2011-05-11 22:10 -0500
        Re: Passing an integer to a function that accepts a void pointer pozz <pozzugno@gmail.com> - 2011-05-12 19:44 +0200
          Re: Passing an integer to a function that accepts a void pointer Shao Miller <sha0.miller@gmail.com> - 2011-05-12 14:16 -0400
            Re: Passing an integer to a function that accepts a void pointer pozz <pozzugno@gmail.com> - 2011-05-12 21:21 +0200
              Re: Passing an integer to a function that accepts a void pointer Shao Miller <sha0.miller@gmail.com> - 2011-05-12 16:05 -0400
                Re: Passing an integer to a function that accepts a void pointer pozz <pozzugno@gmail.com> - 2011-05-13 23:39 +0200
                Re: Passing an integer to a function that accepts a void pointer Dr Nick <3-nospam@temporary-address.org.uk> - 2011-05-14 09:41 +0100
          Re: Passing an integer to a function that accepts a void pointer Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-05-12 22:07 -0400
            Re: Passing an integer to a function that accepts a void pointer pozz <pozzugno@gmail.com> - 2011-05-13 23:12 +0200
              Re: Passing an integer to a function that accepts a void pointer Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-05-13 23:30 -0400
  Re: Passing an integer to a function that accepts a void pointer Columbus sailed the ocean China Blue <chine.bleu@yahoo.com> - 2011-05-11 04:03 -0700
    Re: Passing an integer to a function that accepts a void pointer Heikki Kallasjoki <see@end.of.message.invalid> - 2011-05-11 13:03 +0000
      Re: Passing an integer to a function that accepts a void pointer Columbus sailed the ocean China Blue <chine.bleu@yahoo.com> - 2011-05-11 06:46 -0700
        Re: Passing an integer to a function that accepts a void pointer Keith Thompson <kst-u@mib.org> - 2011-05-11 08:24 -0700
          Re: Passing an integer to a function that accepts a void pointer Columbus sailed the ocean China Blue <chine.bleu@yahoo.com> - 2011-05-11 08:44 -0700
            Re: Passing an integer to a function that accepts a void pointer Keith Thompson <kst-u@mib.org> - 2011-05-11 08:58 -0700
              Re: Passing an integer to a function that accepts a void pointer gazelle@shell.xmission.com (Kenny McCormack) - 2011-05-11 17:38 +0000
                Re: Passing an integer to a function that accepts a void pointer Kenneth Brody <kenbrody@spamcop.net> - 2011-05-11 14:57 -0400
                Re: Passing an integer to a function that accepts a void pointer Paul N <gw7rib@aol.com> - 2011-05-11 14:06 -0700
                Re: Passing an integer to a function that accepts a void pointer Michael Press <rubrum@pacbell.net> - 2011-05-12 13:59 -0700
                Re: Passing an integer to a function that accepts a void pointer Keith Thompson <kst-u@mib.org> - 2011-05-12 14:12 -0700
                Re: Passing an integer to a function that accepts a void pointer Columbus sailed the ocean China Blue <chine.bleu@yahoo.com> - 2011-05-12 15:27 -0700
                Re: Passing an integer to a function that accepts a void pointer Seebs <usenet-nospam@seebs.net> - 2011-05-12 22:37 +0000
                Re: Passing an integer to a function that accepts a void pointer Ian Collins <ian-news@hotmail.com> - 2011-05-13 10:41 +1200
                Re: Passing an integer to a function that accepts a void pointer Shao Miller <sha0.miller@gmail.com> - 2011-05-12 17:57 -0500
                Re: Passing an integer to a function that accepts a void pointer Ian Collins <ian-news@hotmail.com> - 2011-05-13 11:05 +1200
                Re: Passing an integer to a function that accepts a void pointer Seebs <usenet-nospam@seebs.net> - 2011-05-12 23:19 +0000
                Re: Passing an integer to a function that accepts a void pointer Keith Thompson <kst-u@mib.org> - 2011-05-12 16:32 -0700
                Re: Passing an integer to a function that accepts a void pointer Shao Miller <sha0.miller@gmail.com> - 2011-05-12 19:13 -0500
                Re: Passing an integer to a function that accepts a void pointer Keith Thompson <kst-u@mib.org> - 2011-05-12 18:18 -0700
                Re: Passing an integer to a function that accepts a void pointer Keith Thompson <kst-u@mib.org> - 2011-05-12 16:18 -0700
                Re: Passing an integer to a function that accepts a void pointer Tobias Blass <tobiasblass@gmx.net> - 2011-05-13 08:24 +0000
                Re: Passing an integer to a function that accepts a void pointer Columbus sailed the ocean China Blue <chine.bleu@yahoo.com> - 2011-05-13 01:33 -0700
                Re: Passing an integer to a function that accepts a void pointer Seebs <usenet-nospam@seebs.net> - 2011-05-13 08:36 +0000
                Re: Passing an integer to a function that accepts a void pointer "madamemandm@yahoo.com" <madamemandm@yahoo.com> - 2011-05-13 07:08 -0700
                Re: Passing an integer to a function that accepts a void pointer Keith Thompson <kst-u@mib.org> - 2011-05-12 15:59 -0700
            Re: Passing an integer to a function that accepts a void pointer Seebs <usenet-nospam@seebs.net> - 2011-05-11 21:46 +0000
              Re: Passing an integer to a function that accepts a void pointer Columbus sailed the ocean China Blue <chine.bleu@yahoo.com> - 2011-05-12 00:56 -0700
                Re: Passing an integer to a function that accepts a void pointer Ian Collins <ian-news@hotmail.com> - 2011-05-12 20:06 +1200
                Re: Passing an integer to a function that accepts a void pointer Heikki Kallasjoki <see@end.of.message.invalid> - 2011-05-12 08:59 +0000
                Re: Passing an integer to a function that accepts a void pointer Ian Collins <ian-news@hotmail.com> - 2011-05-13 10:39 +1200
        Re: Passing an integer to a function that accepts a void pointer Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-05-12 06:51 -0400
          Re: Passing an integer to a function that accepts a void pointer Columbus sailed the ocean China Blue <chine.bleu@yahoo.com> - 2011-05-12 04:08 -0700
            Re: Passing an integer to a function that accepts a void pointer Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-05-12 07:33 -0400
            Re: Passing an integer to a function that accepts a void pointer Keith Thompson <kst-u@mib.org> - 2011-05-12 07:58 -0700
              Re: Passing an integer to a function that accepts a void pointer gazelle@shell.xmission.com (Kenny McCormack) - 2011-05-12 15:23 +0000
              Re: Passing an integer to a function that accepts a void pointer Shao Miller <sha0.miller@gmail.com> - 2011-05-12 13:36 -0400
                Re: Passing an integer to a function that accepts a void pointer Keith Thompson <kst-u@mib.org> - 2011-05-12 12:03 -0700
            Re: Passing an integer to a function that accepts a void pointer Seebs <usenet-nospam@seebs.net> - 2011-05-12 15:57 +0000
          Re: Passing an integer to a function that accepts a void pointer Michael Press <rubrum@pacbell.net> - 2011-05-12 14:14 -0700
            Re: Passing an integer to a function that accepts a void pointer Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-05-12 22:20 -0400
              Re: Passing an integer to a function that accepts a void pointer Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-05-14 02:39 +0100
  Re: Passing an integer to a function that accepts a void pointer Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-05-11 07:37 -0400
  Re: Passing an integer to a function that accepts a void pointer James Kuyper <jameskuyper@verizon.net> - 2011-05-11 09:42 -0400
  Re: Passing an integer to a function that accepts a void pointer Datesfat Chicks <datesfat.chicks@gmail.com> - 2011-05-11 11:53 -0400
    Re: Passing an integer to a function that accepts a void pointer Fred <fred.l.kleinschmidt@boeing.com> - 2011-05-11 10:44 -0700
      Re: Passing an integer to a function that accepts a void pointer Datesfat Chicks <datesfat.chicks@gmail.com> - 2011-05-12 07:58 -0400
    Re: Passing an integer to a function that accepts a void pointer Dr Nick <3-nospam@temporary-address.org.uk> - 2011-05-11 21:27 +0100

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