Re: Somw questions [ MAYBE OFFTOPIC ]

[Amol Mohite <amol@m-net.arbornet.org>]

> A NULL pointer is just yet another invalid address.  There is no special
> test for a NULL pointer.  Most probably for example (char *)0x12345678 will
> be invalid as a pointer as well and treated the same.  The CPU detects this
> when the TLB doesn't have a translation valid for the access being attempted.
> 


Yes but how does it know it is a null pointer ?

On that note, when c does not allow u to dereference a void pointer , is
this compiler  doing the trick ?

Ok , about the expand down attribute, thats how 32 bit windows does it, so
i was wondering if linux also does the same.

16 bit windows accesses a null pointer with a 0: descriptor.

Apparently intel allows u to load a 0 but not dererence it.



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