🚀 go-pugleaf

Steve Clamage (clamage@Eng.Sun.COM) wrote:
: In article ceo@engnews1.Eng.Sun.COM, "joe (j.) halpin" <jhalpin@bnr.ca>
: writes:
: >
: >In 3.7.3.2.4 the January working paper says:
: >
: >4 A deallocation function can free the storage referenced by the pointer
: >  given  as  its  argument and renders the pointer invalid.  The storage
: >  can be made available for further allocation.  An invalid pointer con-
: >  tains an unusable value:  it cannot even be used in an expression.
[...]
: The reason for the odd-looking condition (which follows the C
: standard) is to allow architectures which validate pointers in
: hardware to be standard-conforming. Example:
[...]
: You can't do anything useful in portable code with uninitialized pointers,
: or pointers which point to objects which are no longer available. The
: standard allows the implementation a great deal of leeway in trying to
: help by identifying such invalid uses.

... just as for arithmetic exceptions, which also engender "undefined
behavior."  But why the leeway to, say, reformat the disk, rather
than specifying the normal practice, which is to invoke a signal
handler, thereby, keeping the behavior defined?

Tom Payne (thp@cs.ucr.edu)


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