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Groups > comp.lang.c > #99561

Re: sscanf error checking

From raltbos@xs4all.nl (Richard Bos)
Newsgroups comp.lang.c
Subject Re: sscanf error checking
Date 2016-12-15 20:20 +0000
Organization Go wash your mouth.
Message-ID <5852fa62.4681734@news.xs4all.nl> (permalink)
References <o2rp71$3e7$1@dont-email.me> <k2c35ctbq4lg3bnllpfbt15lc8l2qsfodm@4ax.com> <77a15075-1f22-405c-a896-061dda988473@googlegroups.com>

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supercat@casperkitty.com wrote:

> On Wednesday, December 14, 2016 at 2:52:04 PM UTC-6, robert...@yahoo.com wrote:
> > IMO, the *scanf() and ato*() functions are pretty much of no use
> > outside of toy problems, the lack of meaningful error handling being
> > the biggest issue.  YMMV.
> 
> Many programs are intended only for use upon validated input.

There is no such thing as validated input; there is only _temporarily_
validated input.

A program using scanf()# and ato*() is only safe if:
- it is used with a single set of input;
- that input is validated _instantly_ before it is fed to the program;
- the program is deleted or incapacitated immediately afterward.

(A program using gets() is, of course, unsafe even then.)

Richard

# sscanf() and fscanf() are _slightly_ better.

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Thread

sscanf error checking BartC <bc@freeuk.com> - 2016-12-14 15:42 +0000
  Re: sscanf error checking John Gordon <gordon@panix.com> - 2016-12-14 15:58 +0000
    Re: sscanf error checking Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2016-12-14 11:14 -0500
  Re: sscanf error checking gazelle@shell.xmission.com (Kenny McCormack) - 2016-12-14 16:11 +0000
    Re: sscanf error checking BartC <bc@freeuk.com> - 2016-12-14 17:51 +0000
      Re: sscanf error checking gazelle@shell.xmission.com (Kenny McCormack) - 2016-12-14 18:09 +0000
      Re: sscanf error checking Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-12-14 19:49 +0000
        Re: sscanf error checking BartC <bc@freeuk.com> - 2016-12-14 20:43 +0000
  Re: sscanf error checking Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-12-14 16:40 +0000
  Re: sscanf error checking Keith Thompson <kst-u@mib.org> - 2016-12-14 09:34 -0800
  Re: sscanf error checking Robert Wessel <robertwessel2@yahoo.com> - 2016-12-14 14:52 -0600
    Re: sscanf error checking supercat@casperkitty.com - 2016-12-15 07:24 -0800
      Re: sscanf error checking Keith Thompson <kst-u@mib.org> - 2016-12-15 11:26 -0800
        Re: sscanf error checking Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-12-15 15:35 -0800
          Re: sscanf error checking Keith Thompson <kst-u@mib.org> - 2016-12-15 16:28 -0800
            Re: sscanf error checking Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-12-15 16:37 -0800
              Re: sscanf error checking Robert Wessel <robertwessel2@yahoo.com> - 2016-12-26 17:25 -0600
        Re: sscanf error checking supercat@casperkitty.com - 2016-12-15 16:38 -0800
      Re: sscanf error checking raltbos@xs4all.nl (Richard Bos) - 2016-12-15 20:20 +0000
        Re: sscanf error checking Keith Thompson <kst-u@mib.org> - 2016-12-15 12:33 -0800
  sscanf error checking asetofsymbols@gmail.com - 2016-12-16 01:49 -0800
    sscanf error checking asetofsymbols@gmail.com - 2016-12-16 01:53 -0800

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