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Re: snprintf alternatives in iso9899

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Eric Sosman <esosman@comcast-dot-net.invalid> writes:
> On 12/9/2015 4:14 PM, Tim Rentsch wrote:
>> supercat@casperkitty.com writes:
>>
>>> On Tuesday, December 8, 2015 at 8:52:31 AM UTC-6, Ben Bacarisse wrote:
>>>> snprintf was implemented "in the wild" before standardisation, so some
>>>> pre-C99 systems had it.  You could just assume C90+snprintf.
>>>
>>> It's too bad there's no standard for a general-purpose printf
>>> which takes a pointer to a structure with one or two function
>>> pointers and a void*, and uses one of the passed-in functions for
>>> output (passing the void* to the function, which can then use it
>>> as it sees fit).  [...]
>>
>> If the lack bothers you, why don't you write one?  I did.
>
>      It seems to me that a more flexible and powerful approach would
> be to implement such things at the FILE* level.  It's easy to imagine
> things along the lines of
>
> 	FILE *stream = fopen("http://www.c-faq.com/", "r");

The string "http://www.c-faq.com/" could *also* be a valid local file
name.  On a POSIX system, there could be a directory named "http:" with
a subdirectory name "www.c-faq.com".  The trailing "/" means that the
whole thing refers to a directory, but "http://www.c-faq.com/index.html"
could be an ordinary file.

You could set up a "/url" directory, for example, so a file name like
"/url/http://www.c-faq.com/" would unambiguously refer to that URL.

I haven't heard of anyone actually doing that.  The POSIX popen()
function, along with a command like "curl", can do pretty much the same
thing.

One issue is that the things URLs refer to only partially act like
files.

> ... and it wouldn't be a huge departure to offer something like
>
> 	FILE *funcopen(int (*)reader(void*), int (*)writer(void*),
> 	    void *userarg);
> 	FILE *stream = funcopen(NULL, mywriter, buffptr);
>
> Something in this vein would be, I think, superior to running around
> endlessly adding capabilities to printf(), scanf(), fseek(), ...

There's the GNU-specific fopencookie().

-- 
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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snprintf alternatives in iso9899 "Morten W. Petersen" <morphex@gmail.com> - 2015-12-08 06:18 +0100
  Re: snprintf alternatives in iso9899 Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-12-08 02:13 -0800
    Re: snprintf alternatives in iso9899 Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-12-08 10:38 +0000
  Re: snprintf alternatives in iso9899 Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-12-08 14:52 +0000
    Re: snprintf alternatives in iso9899 supercat@casperkitty.com - 2015-12-08 07:15 -0800
      Re: snprintf alternatives in iso9899 Tim Rentsch <txr@alumni.caltech.edu> - 2015-12-09 13:14 -0800
        Re: snprintf alternatives in iso9899 Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-12-09 16:28 -0500
          Re: snprintf alternatives in iso9899 Ian Collins <ian-news@hotmail.com> - 2015-12-10 10:35 +1300
            Re: snprintf alternatives in iso9899 Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-12-09 16:49 -0500
              Re: snprintf alternatives in iso9899 Ian Collins <ian-news@hotmail.com> - 2015-12-10 11:00 +1300
          Re: snprintf alternatives in iso9899 supercat@casperkitty.com - 2015-12-09 14:02 -0800
            Re: snprintf alternatives in iso9899 Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-12-10 02:41 -0800
          The FILE * pattern [was Re: snprintf alternatives in iso9899] Richard Heathfield <rjh@cpax.org.uk> - 2015-12-09 22:02 +0000
          Re: snprintf alternatives in iso9899 Keith Thompson <kst-u@mib.org> - 2015-12-09 14:49 -0800
    Re: snprintf alternatives in iso9899 Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-12-08 16:47 +0000
      Re: snprintf alternatives in iso9899 Keith Thompson <kst-u@mib.org> - 2015-12-08 09:18 -0800
      Re: snprintf alternatives in iso9899 Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-12-08 17:27 +0000
  Re: snprintf alternatives in iso9899 Keith Thompson <kst-u@mib.org> - 2015-12-08 08:41 -0800
    Re: snprintf alternatives in iso9899 "Morten W. Petersen" <morphex@gmail.com> - 2015-12-09 02:56 +0100
      Re: snprintf alternatives in iso9899 Ian Collins <ian-news@hotmail.com> - 2015-12-09 15:04 +1300
        Re: snprintf alternatives in iso9899 Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-12-09 02:16 +0000
      Re: snprintf alternatives in iso9899 Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-12-09 04:49 -0800
        Re: snprintf alternatives in iso9899 "Morten W. Petersen" <morphex@gmail.com> - 2015-12-10 08:00 +0100

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