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Groups > comp.lang.c++ > #70729
| From | Bo Persson <bo@bo-persson.se> |
|---|---|
| Newsgroups | comp.lang.c++ |
| Subject | Re: What is the data structure of a NULL? |
| Date | 2019-12-28 11:28 +0100 |
| Message-ID | <h6op24Fo1igU1@mid.individual.net> (permalink) |
| References | <qu5spt$ad8$1@dont-email.me> <h6nbqkFctnvU3@mid.individual.net> <qu5uko$7lm$2@dont-email.me> |
On 2019-12-27 at 22:55, T wrote:
> On 2019-12-27 13:36, Ian Collins wrote:
>> On 28/12/2019 10:24, T wrote:
>>> Hi All,
>>>
>>> In C++, when you make a call to Windows Kernel32.dll
>>> and it wants a NULL for one or more of its parameters,
>>> what exactly is the structure of a NULL? A 32 bit
>>> word full of zeros?
>>
>> The C standard defines a null pointer as
>>
>> "An integer constant expression with the value 0, or such an
>> expression cast to type void *, is called a null pointer constant."
>>
>
> Since Kernel32.dll uses 32 bit words as pointers, a 32 bit
> word will all zero's it is. Thank you!
>
Please note that, historically, the "32" was added to indicate that it
is no longer a 16-bit Windows (like Windows 1, 2, and 3 was).
When moving from 32 to 64 bits, the names were *not* changed. :-)
So, the suffix 32 just means "not 16".
Bo Persson
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What is the data structure of a NULL? T <T@invalid.invalid> - 2019-12-27 13:24 -0800
Re: What is the data structure of a NULL? Ian Collins <ian-news@hotmail.com> - 2019-12-28 10:36 +1300
Re: What is the data structure of a NULL? T <T@invalid.invalid> - 2019-12-27 13:55 -0800
Re: What is the data structure of a NULL? Bo Persson <bo@bo-persson.se> - 2019-12-28 11:28 +0100
Re: What is the data structure of a NULL? James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-12-27 20:50 -0500
Re: What is the data structure of a NULL? T <T@invalid.invalid> - 2019-12-28 17:14 -0800
Re: What is the data structure of a NULL? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2020-01-10 20:56 -0800
Re: What is the data structure of a NULL? "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2019-12-27 22:42 +0100
Re: What is the data structure of a NULL? T <T@invalid.invalid> - 2019-12-27 13:55 -0800
Re: What is the data structure of a NULL? "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2019-12-27 23:10 +0100
Re: What is the data structure of a NULL? Öö Tiib <ootiib@hot.ee> - 2019-12-27 14:15 -0800
Re: What is the data structure of a NULL? T <T@invalid.invalid> - 2019-12-27 14:24 -0800
Re: What is the data structure of a NULL? Öö Tiib <ootiib@hot.ee> - 2019-12-27 14:41 -0800
Re: What is the data structure of a NULL? Manfred <noname@add.invalid> - 2019-12-28 20:11 +0100
Re: What is the data structure of a NULL? T <T@invalid.invalid> - 2019-12-28 17:16 -0800
Re: What is the data structure of a NULL? Manfred <noname@invalid.add> - 2019-12-29 17:52 +0100
Re: What is the data structure of a NULL? T <T@invalid.invalid> - 2019-12-29 12:21 -0800
Re: What is the data structure of a NULL? Bart <bc@freeuk.com> - 2019-12-28 01:46 +0000
Re: What is the data structure of a NULL? T <T@invalid.invalid> - 2019-12-28 17:17 -0800
Re: What is the data structure of a NULL? Bart <bc@freeuk.com> - 2019-12-29 01:42 +0000
Re: What is the data structure of a NULL? T <T@invalid.invalid> - 2019-12-28 18:39 -0800
Re: What is the data structure of a NULL? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2019-12-28 02:14 -0800
Re: What is the data structure of a NULL? Ned Latham <nedlatham@woden.valhalla.oz> - 2019-12-28 08:33 -0600
Re: What is the data structure of a NULL? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2019-12-28 13:22 -0800
Re: What is the data structure of a NULL? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2019-12-28 16:02 -0800
Re: What is the data structure of a NULL? Ned Latham <nedlatham@woden.valhalla.oz> - 2019-12-28 22:37 -0600
Re: What is the data structure of a NULL? Ned Latham <nedlatham@woden.valhalla.oz> - 2019-12-28 22:37 -0600
Re: What is the data structure of a NULL? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2019-12-28 21:12 -0800
Re: What is the data structure of a NULL? Ned Latham <nedlatham@woden.valhalla.oz> - 2019-12-29 04:45 -0600
Re: What is the data structure of a NULL? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2019-12-29 13:31 -0800
Re: What is the data structure of a NULL? Ned Latham <nedlatham@woden.valhalla.oz> - 2019-12-29 21:34 -0600
Re: What is the data structure of a NULL? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2019-12-29 22:48 -0800
Re: What is the data structure of a NULL? James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-12-29 20:20 -0500
Re: What is the data structure of a NULL? Ned Latham <nedlatham@woden.valhalla.oz> - 2019-12-29 21:50 -0600
Re: What is the data structure of a NULL? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2019-12-29 22:46 -0800
Re: What is the data structure of a NULL? David Brown <david.brown@hesbynett.no> - 2019-12-30 10:25 +0100
Re: What is the data structure of a NULL? Ned Latham <nedlatham@woden.valhalla.oz> - 2019-12-30 05:20 -0600
Re: What is the data structure of a NULL? David Brown <david.brown@hesbynett.no> - 2019-12-30 17:24 +0100
Re: What is the data structure of a NULL? Ned Latham <nedlatham@woden.valhalla.oz> - 2019-12-30 17:22 -0600
Re: What is the data structure of a NULL? David Brown <david.brown@hesbynett.no> - 2019-12-31 13:57 +0100
Re: What is the data structure of a NULL? Ned Latham <nedlatham@woden.valhalla.oz> - 2019-12-31 07:33 -0600
Re: What is the data structure of a NULL? David Brown <david.brown@hesbynett.no> - 2019-12-31 15:45 +0100
Re: What is the data structure of a NULL? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-12-30 18:16 +0000
Re: What is the data structure of a NULL? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2019-12-30 10:45 -0800
Re: What is the data structure of a NULL? Ned Latham <nedlatham@woden.valhalla.oz> - 2019-12-30 17:29 -0600
Re: What is the data structure of a NULL? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2019-12-30 21:48 -0800
Re: What is the data structure of a NULL? Ned Latham <nedlatham@woden.valhalla.oz> - 2019-12-30 04:19 -0600
Re: What is the data structure of a NULL? David Brown <david.brown@hesbynett.no> - 2019-12-30 17:27 +0100
Re: What is the data structure of a NULL? Öö Tiib <ootiib@hot.ee> - 2019-12-30 03:25 -0800
Re: What is the data structure of a NULL? Jorgen Grahn <grahn+nntp@snipabacken.se> - 2019-12-31 21:54 +0000
Re: What is the data structure of a NULL? James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-12-30 06:03 -0800
Re: What is the data structure of a NULL? Ned Latham <nedlatham@woden.valhalla.oz> - 2019-12-30 17:01 -0600
Re: What is the data structure of a NULL? James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-12-30 21:42 -0500
Re: What is the data structure of a NULL? Ned Latham <nedlatham@woden.valhalla.oz> - 2019-12-31 06:03 -0600
Re: What is the data structure of a NULL? Öö Tiib <ootiib@hot.ee> - 2019-12-31 06:17 -0800
Re: What is the data structure of a NULL? Ned Latham <nedlatham@woden.valhalla.oz> - 2019-12-31 10:46 -0600
Re: What is the data structure of a NULL? Melzzzzz <Melzzzzz@zzzzz.com> - 2019-12-31 16:57 +0000
Re: What is the data structure of a NULL? David Brown <david.brown@hesbynett.no> - 2019-12-31 18:15 +0100
Re: What is the data structure of a NULL? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2019-12-31 11:20 -0800
Re: What is the data structure of a NULL? David Brown <david.brown@hesbynett.no> - 2020-01-01 17:01 +0100
Re: What is the data structure of a NULL? Ned Latham <nedlatham@woden.valhalla.oz> - 2019-12-31 11:21 -0600
Re: What is the data structure of a NULL? Jorgen Grahn <grahn+nntp@snipabacken.se> - 2019-12-31 21:37 +0000
Re: What is the data structure of a NULL? James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-12-31 15:21 -0800
Re: What is the data structure of a NULL? Chris Vine <chris@cvine--nospam--.freeserve.co.uk> - 2019-12-31 17:26 +0000
Re: What is the data structure of a NULL? James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-12-31 23:30 -0500
Re: What is the data structure of a NULL? Manfred <noname@add.invalid> - 2020-01-01 18:10 +0100
Re: What is the data structure of a NULL? James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-01-01 12:21 -0500
Re: What is the data structure of a NULL? Chris Vine <chris@cvine--nospam--.freeserve.co.uk> - 2019-12-31 15:20 +0000
Re: What is the data structure of a NULL? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2019-12-31 11:11 -0800
Re: What is the data structure of a NULL? Chris Vine <chris@cvine--nospam--.freeserve.co.uk> - 2019-12-31 19:47 +0000
Re: What is the data structure of a NULL? James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-12-31 10:27 -0800
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