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Re: isspace() executes without ctype header?

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supercat@casperkitty.com writes:
> On Wednesday, June 14, 2017 at 2:03:52 PM UTC-5, Keith Thompson wrote:
>> Both cman74.pdf and cman.pdf (from 1975, I think) says that char
>> arguments are promoted to int, and float arguments to double.
>> (char, int, float, and double were the only numeric types.)
>> No other conversions are specified.
>
> The layout of passed arguments was effectively documented by the sample
> printf function, and there were no aliasing rules.  I will grant that it
> is unclear whether implementations would have been expected to ensure that
> a memcpy-style function could be invoked without requiring a caller-side
> cast, but I don't recall anything in that manual that would suggest that
> such a cast would be needed.

The sample printf implementation in cman.pdf accepts arguments of types
int, double, and char* (the latter points to a string for "%s").  The
code that handles the arguments increments a pointer to int for int
arguments, a pointer to double for double arguments, and a pointer to
char* for char* arguments.  It certainly assumes that arguments are
allocated sequentially and in order, but I see no assumptions about the
representations of different pointer types.  And it clearly says, "It
should be evident, though, that such techniques are implementation
dependent."

[...]

-- 
Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
Working, but not speaking, for JetHead Development, Inc.
"We must do something.  This is something.  Therefore, we must do this."
    -- Antony Jay and Jonathan Lynn, "Yes Minister"

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isspace() executes without ctype header? DFS <nospam@dfs.com> - 2017-06-13 21:13 -0400
  Re: isspace() executes without ctype header? Ian Collins <ian-news@hotmail.com> - 2017-06-14 13:20 +1200
    Re: isspace() executes without ctype header? DFS <nospam@dfs.com> - 2017-06-13 21:33 -0400
      Re: isspace() executes without ctype header? Ian Collins <ian-news@hotmail.com> - 2017-06-14 13:35 +1200
        Re: isspace() executes without ctype header? DFS <nospam@dfs.com> - 2017-06-13 22:31 -0400
          Re: isspace() executes without ctype header? Ian Collins <ian-news@hotmail.com> - 2017-06-14 14:40 +1200
  Re: isspace() executes without ctype header? Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2017-06-13 21:49 -0400
  Re: isspace() executes without ctype header? Tim Rentsch <txr@alumni.caltech.edu> - 2017-06-13 19:20 -0700
    Re: isspace() executes without ctype header? DFS <nospam@dfs.com> - 2017-06-13 23:04 -0400
      Re: isspace() executes without ctype header? asetofsymbols@gmail.com - 2017-06-13 23:07 -0700
      Re: isspace() executes without ctype header? Tim Rentsch <txr@alumni.caltech.edu> - 2017-06-14 08:26 -0700
        Re: isspace() executes without ctype header? bartc <bc@freeuk.com> - 2017-06-14 17:29 +0100
          Re: isspace() executes without ctype header? Keith Thompson <kst-u@mib.org> - 2017-06-14 09:46 -0700
            Re: isspace() executes without ctype header? bartc <bc@freeuk.com> - 2017-06-14 17:54 +0100
              Re: isspace() executes without ctype header? Keith Thompson <kst-u@mib.org> - 2017-06-14 10:17 -0700
              Re: isspace() executes without ctype header? supercat@casperkitty.com - 2017-06-14 10:48 -0700
                Re: isspace() executes without ctype header? Keith Thompson <kst-u@mib.org> - 2017-06-14 12:03 -0700
                Re: isspace() executes without ctype header? supercat@casperkitty.com - 2017-06-14 12:48 -0700
                Re: isspace() executes without ctype header? Keith Thompson <kst-u@mib.org> - 2017-06-14 13:06 -0700
            Re: isspace() executes without ctype header? Tim Rentsch <txr@alumni.caltech.edu> - 2017-06-16 23:14 -0700
  Re: isspace() executes without ctype header? bartc <bc@freeuk.com> - 2017-06-14 11:18 +0100
    Re: isspace() executes without ctype header? Keith Thompson <kst-u@mib.org> - 2017-06-14 09:35 -0700
      Re: isspace() executes without ctype header? bartc <bc@freeuk.com> - 2017-06-14 17:47 +0100
        Re: isspace() executes without ctype header? supercat@casperkitty.com - 2017-06-14 10:19 -0700
          Re: isspace() executes without ctype header? Keith Thompson <kst-u@mib.org> - 2017-06-14 10:29 -0700
        Re: isspace() executes without ctype header? Keith Thompson <kst-u@mib.org> - 2017-06-14 10:21 -0700
          Re: isspace() executes without ctype header? bartc <bc@freeuk.com> - 2017-06-14 19:12 +0100
            Re: isspace() executes without ctype header? Keith Thompson <kst-u@mib.org> - 2017-06-14 12:12 -0700
            Re: isspace() executes without ctype header? joel.rees@gmail.com - 2017-06-16 17:56 -0700
              Re: isspace() executes without ctype header? supercat@casperkitty.com - 2017-06-17 10:20 -0700
                Re: isspace() executes without ctype header? Robert Wessel <robertwessel2@yahoo.com> - 2017-06-18 00:25 -0500
                Re: isspace() executes without ctype header? supercat@casperkitty.com - 2017-06-19 09:01 -0700
                Re: isspace() executes without ctype header? Robert Wessel <robertwessel2@yahoo.com> - 2017-06-19 21:59 -0500

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