Re: Printf and scanf

[joy merwin monteiro <joy.merwin@gmail.com>]

Now you have piqued my interest.......
what special characters??
any place on the net I can read up on this?

Joy


On 6/27/05, Andriot <andriot@6wind.com> wrote:
> Hendrik Visage wrote:
> 
> >On 6/5/05, Ankit Jain <ankitjain1580@yahoo.com> wrote:
> >
> >
> >
> >>i just want to know how scanf function can be used on
> >>the place of printf and vice versa
> >>
> >>
> >
> >In the Obfuscated C contest one of the first/early entries is one that
> >states "Using read to write" (Or something to similar extend, or
> >perhaps even using scanf to print). Reading that code is hackery, and
> >from my first glance at the code, it was don't with quote and macro
> >hackery.
> >
> >Thus you could #define scanf __prinf and #define printf __scanf... or
> >something with similar confusing
> >
> >
> 
> Of course, it is not possible to use directly printf like a scanf ;)
> But you can use printf to write some values into arguments when you call
> the function. This uses special caracters you put in the format string.
> And this should prevent you to call printf with a string the user wrote,
> because this is a very big security hole.
> 
> JP
> 
> 
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-- 
<ed__> riel: if it were a vax, gcc would probably be an opcode

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