OpenEuphoria

Re: realloc() failing under DOS (why it does'nt ...)

• Posted by Robert Craig <rds at RapidEuphoria.com> Nov 08, 2001
• 465 views

pseudonomus writes:
>       s = (char*)Realloc(s, i);
>       s[i-1] = 'X';
>       s[i] = 0; /* EOS */

In C, if s is a pointer to i bytes, then s[i] is *not* a valid element.
The subscripts run from 0 to i-1. You are writing a byte beyond
the allocated space. Sometimes this won't matter. Other times
it will lead to disaster.

> Yet this code in Eu:
> ...
> works perfectly fast, and does not crash Euphoria.
> ...
> Is it a fluke that Euphoria does not fail when
> appending?

I've been pulling my hair out for many years, working
with malloc, realloc and friends. I think I have most of the 
bugs out now.  Buy the source in 2 weeks and learn all 
the tricks of the trade.   

Regards,
   Rob Craig
   Rapid Deployment Software
   http://www.RapidEuphoria.com