initializing null pointers

[jans at stalker.UUCP]

In article <7614 at utzoo.UUCP> henry at utzoo.UUCP (Henry Spencer) writes:
>> What about pointer arrays allocated with calloc()?  Does one have to
>> initialize all the elements in a loop to be portable...
>
>Fraid so.  What you might do, though, if you are willing to risk some small
>degree of unportability for the sake of efficiency, is first test an element
>of the array for equality to NULL...
>
>The small portability risk in this is the possibility that an all-zeros
>pointer might have magic properties (e.g. trap on any use of it).

Or that you might, by chance, have tested a pointer that had been NULL in a
previous life!

The most portable thing to do is NEVER dereference a pointer that has not been
initialized.  Some micro compilers I've used don't even initialize automatics!

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