[PATCH v2 3/4] Say malloc (0) != NULL is now common; resection

[DJ Delorie]

Paul Eggert <eggert@cs.ucla.edu> writes:
>> We should add a note about how to be portable (that's the purpose of
>> this section, yes? ;) like "Thus, portable programs should never pass a
>> size of zero to allocation functions."
>
> I wouldn't go that far, as it's portable to pass 0 to malloc, so long as 
> you're willing to deal with the resulting null pointer.

Posix says "If the size of the space requested is 0, the behavior is
implementation-defined".  An application that can accept more than one
implementation's definition has been ported, but is not portable.  Yes,
posix defines two possible behaviors, but still leaves the non-null
returned pointer's access undefined.

To fully avoid undefined or implementation-defined behavior, a portable
program should avoid this completely by never passing zero to malloc.