malloc() behavior (was: Pointer please)

[James Jacobsen]

You learn something new every day(probably not how to spell).  I'm not  
a very experienced programmer.  I actual did not know about those  
debugging tools.  Thanks. :)

--James

On 10/05/03 22:31:09, Dan Nelson wrote:
> In the last episode (Oct 05), James Jacobsen said:
> > On 10/05/03 21:42:23, Robert Huff wrote:
> > >James Jacobsen writes:
> > >>  It does not matter what freebsd does, C does not require that
> > >>  malloc initialize space according to Kernighan and Ritchie.
> > >
> > >I knew that, and agree depending on a particular behavior is bad
> > >programming practice.  That said, there's a lot of "bad
> programmers"
> > >out there ....
> >
> > What's really bad, is that freebsd could potentally change there
> > behavor down the line.  Its probably dictated by the way kernel
> > dezined, meaning they may do whats the cheapist.  I would.  If they
> > do its go to lead to some weird behavior.  :-)
> 
> There's nothing bad about it.  FreeBSD follows the standards.  The
> debugging flags simply change what the undefined behaviour is.  If  
> you
> malloc a block of memory, you cannot rely on what data it currently
> contains.  FreeBSD lets you zero it, fill it with a set value, or
> leave
> it.
> 
> Programs exhibiting weird behaviour under any of those three cases  
> are
> broken.  Most debugging mallocs will trigger it, purify will probably
> catch it (never used it), and valgrind under Linux will definitely
> catch it.
> 
> --
> 	Dan Nelson
> 	dnelson at allantgroup.com
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