safe to delete null pointer?

[Songling]

Hi gurus,

Just learnt from my co-worker that it's safe to delete a null pointer. I
tried it on sun box
(and linux), nothing bad happens. So it seems to be true. But does it apply
to all platforms?

Also if I delete a pointer twice, and don't nullify the pointer after the
first delete, it's going
to trap. If I do the nullify, no trap. Does it just confirm that it's safe
to delete null pointer?

Btw I ran my test on SunOS 5.8 and Linux 2.4.18-3.

Thanks for your reply!

Songling

 

[Artie Gold]

Hi gurus,

Just learnt from my co-worker that it's safe to delete a null pointer. I
tried it on sun box
(and linux), nothing bad happens. So it seems to be true. But does it apply
to all platforms?

Also if I delete a pointer twice, and don't nullify the pointer after the
first delete, it's going
to trap. If I do the nullify, no trap. Does it just confirm that it's safe
to delete null pointer?

Btw I ran my test on SunOS 5.8 and Linux 2.4.18-3.

Thanks for your reply!

Songling

Calling delete on a null pointer is a no-op -- and, by the standard, no
problem. Of course, the fact that you're deleting a null pointer may
indicate the existence of a bug in your program -- but not necessarily.

HTH,
--ag

 

[Sumit Rajan]

Hi gurus,

Just learnt from my co-worker that it's safe to delete a null pointer. I
tried it on sun box
(and linux), nothing bad happens. So it seems to be true. But does it apply
to all platforms?

Also if I delete a pointer twice, and don't nullify the pointer after the
first delete, it's going
to trap. If I do the nullify, no trap. Does it just confirm that it's safe
to delete null pointer?

Deleting a null pointer is safe. 5.3.5/2 of the Standard:

"In either alternative, if the value of the operand of delete is the
null pointer the operation has no effect."

Regards,
Sumit.

 

[Stuart Gerchick]

Hi gurus,

Just learnt from my co-worker that it's safe to delete a null pointer. I
tried it on sun box
(and linux), nothing bad happens. So it seems to be true. But does it apply
to all platforms?

Also if I delete a pointer twice, and don't nullify the pointer after the
first delete, it's going
to trap. If I do the nullify, no trap. Does it just confirm that it's safe
to delete null pointer?

Btw I ran my test on SunOS 5.8 and Linux 2.4.18-3.

Thanks for your reply!

Songling

Deleting a null poiner is fine. It will have no effect and will behave as expected