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Re: size_t, when to use it? (learning)

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On 2014-04-19, glen herrmannsfeldt <gah@ugcs.caltech.edu> wrote:
> william@wilbur.25thandclement.com wrote:
>
> (snip)
>
>> I've fixed several bugs in my career where people used `sizeof (type)',
>> where type was wrong. I've yet to encounter a similar bug where 
>> people used `sizeof object'. Anecdotal, but the fact of the 
>> matter is that `sizeof object' states more precisely what you 
>> want, and precision is important when programming.
>  
>> People keep repeating that rule for specific reasons, none of 
>>which are to oppress you.
>
> Yes if you sizeof(type) someone could change the type, such that
> it didn't match.
>
> But one could also change the name such that it didn't match.

In the expression sizeof(X) or sizeof X, the compiler doesn't verify
that X agrees with anything in the surrounding code semantically;
the sizeof expression stands completely alone.

Now in sizeof(X), where X is an identifier, X could contain a typo such
that it happens to match a declared identifier.  Since the parentheses are
present, this wrong X can be a typedef name or an object.

If X has a typo in sizeof X, X can only be an object, not a type; there is a
smaller "typo target space". There are usually fewer declared objects than
there are declared type names and objects.

If sizeof *X has a typo in identifier X, the typo has to land on an
identifier which is declared such that it takes a unary * operator.
There are usually fewer declared pointers than there are declared objects.

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size_t, when to use it? (learning) G G <gdotone@gmail.com> - 2014-04-10 08:11 -0700
  Re: size_t, when to use it? (learning) James Kuyper <jameskuyper@verizon.net> - 2014-04-10 11:42 -0400
    Re: size_t, when to use it? (learning) G G <gdotone@gmail.com> - 2014-04-10 08:53 -0700
  Re: size_t, when to use it? (learning) Kaz Kylheku <kaz@kylheku.com> - 2014-04-10 16:20 +0000
  Re: size_t, when to use it? (learning) Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-04-10 11:03 -0700
    Re: size_t, when to use it? (learning) Kaz Kylheku <kaz@kylheku.com> - 2014-04-10 18:48 +0000
      Re: size_t, when to use it? (learning) Tim Prince <tprince@computer.org> - 2014-04-10 19:10 -0400
    Re: size_t, when to use it? (learning) glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-04-10 20:03 +0000
      Re: size_t, when to use it? (learning) James Kuyper <jameskuyper@verizon.net> - 2014-04-10 16:15 -0400
        Re: size_t, when to use it? (learning) Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-04-10 13:47 -0700
          Re: size_t, when to use it? (learning) Keith Thompson <kst-u@mib.org> - 2014-04-10 16:27 -0700
          Re: size_t, when to use it? (learning) Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-04-11 01:08 -0700
            Re: size_t, when to use it? (learning) Ian Collins <ian-news@hotmail.com> - 2014-04-11 20:11 +1200
              Re: size_t, when to use it? (learning) Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-04-11 05:06 -0700
                Re: size_t, when to use it? (learning) glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-04-11 17:40 +0000
            Re: size_t, when to use it? (learning) Tim Rentsch <txr@alumni.caltech.edu> - 2014-04-14 18:44 -0700
          Re: size_t, when to use it? (learning) Ike Naar <ike@iceland.freeshell.org> - 2014-04-11 17:44 +0000
            Re: size_t, when to use it? (learning) Keith Thompson <kst-u@mib.org> - 2014-04-11 12:33 -0700
              Re: size_t, when to use it? (learning) Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-04-11 13:23 -0700
                Re: size_t, when to use it? (learning) Tim Rentsch <txr@alumni.caltech.edu> - 2014-04-14 18:48 -0700
                Re: size_t, when to use it? (learning) Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-04-15 00:49 -0700
                Re: size_t, when to use it? (learning) gazelle@shell.xmission.com (Kenny McCormack) - 2014-04-15 08:16 +0000
                Re: size_t, when to use it? (learning) <william@wilbur.25thandClement.com> - 2014-04-18 16:57 -0700
                Re: size_t, when to use it? (learning) glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-04-19 00:25 +0000
                Re: size_t, when to use it? (learning) Kaz Kylheku <kaz@kylheku.com> - 2014-04-19 01:03 +0000
                Re: size_t, when to use it? (learning) Ian Collins <ian-news@hotmail.com> - 2014-04-19 13:04 +1200
                Re: size_t, when to use it? (learning) Keith Thompson <kst-u@mib.org> - 2014-04-18 19:23 -0700
                Re: size_t, when to use it? (learning) <william@wilbur.25thandClement.com> - 2014-04-18 19:32 -0700
                Re: size_t, when to use it? (learning) Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-04-19 03:38 -0700
                Re: size_t, when to use it? (learning) Tim Rentsch <txr@alumni.caltech.edu> - 2014-04-18 09:13 -0700
                Re: size_t, when to use it? (learning) Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-04-18 14:00 -0700
                Re: size_t, when to use it? (learning) Tim Rentsch <txr@alumni.caltech.edu> - 2014-04-20 16:24 -0700
                Re: size_t, when to use it? (learning) Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-04-22 03:36 -0700
              Re: size_t, when to use it? (learning) Ike Naar <ike@iceland.freeshell.org> - 2014-04-12 06:53 +0000
            Re: size_t, when to use it? (learning) Martin Shobe <martin.shobe@yahoo.com> - 2014-04-11 14:42 -0500
              Re: size_t, when to use it? (learning) Ike Naar <ike@iceland.freeshell.org> - 2014-04-12 06:55 +0000
    Re: size_t, when to use it? (learning) G G <gdotone@gmail.com> - 2014-04-10 13:42 -0700
      Re: size_t, when to use it? (learning) James Kuyper <jameskuyper@verizon.net> - 2014-04-10 17:07 -0400
        Re: size_t, when to use it? (learning) G G <gdotone@gmail.com> - 2014-04-10 16:11 -0700
      Re: size_t, when to use it? (learning) Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-04-10 15:08 -0700
        Re: size_t, when to use it? (learning) Keith Thompson <kst-u@mib.org> - 2014-04-10 17:21 -0700
          Re: size_t, when to use it? (learning) gazelle@shell.xmission.com (Kenny McCormack) - 2014-04-11 01:04 +0000
        Re: size_t, when to use it? (learning) Ian Collins <ian-news@hotmail.com> - 2014-04-11 20:06 +1200
    Re: size_t, when to use it? (learning) Tim Rentsch <txr@alumni.caltech.edu> - 2014-04-14 18:33 -0700
    Re: size_t, when to use it? (learning) Rosario193 <Rosario@invalid.invalid> - 2014-04-15 09:37 +0200
  Re: size_t, when to use it? (learning) Ian Collins <ian-news@hotmail.com> - 2014-04-11 20:09 +1200
  Re: size_t, when to use it? (learning) Tim Rentsch <txr@alumni.caltech.edu> - 2014-04-14 18:21 -0700

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