Messages in this thread | | | Date | Sun, 13 Jul 2003 17:42:03 -0400 (EDT) | From | Alan Stern <> | Subject | Re: Style question: Should one check for NULL pointers? |
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On Sat, 12 Jul 2003, Horst von Brand wrote:
> Alan Stern <stern@rowland.harvard.edu> said: > > [...] > > > But if you look very far through the kernel sources you will see many > > occurrences of code similar to this: > > > > static void release(struct xxx *ptr) > > { > > if (!ptr) > > return; > > ... > > > > I can't see any reason for keeping something like that. > > Just like free(3)
NO! Not just like free(). The documentation for free() explicitly states that NULL pointers are valid input and result in no action. A release()-type function, by contrast, is called back from core system code that guarantees it will always pass a pointer to the currently-registered owner of the corresponding resource. If the owner were NULL, the release() function wouldn't have been called in the first place.
Alan Stern
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