On 12/17/2011 07:09 AM, Peter Maydell wrote: >> Typically NULL is defined to be ((void *)0 for C >> (that's the reason why I used a type cast, too). Only for >> C++ it is defined without a type cast. > > The C standard permits plain "0" as a definition of NULL.
POSIX concurs with the C standard that a plain "0" can be used for representing a null pointer, but requires that the macro NULL be defined as ((void*)0) as a tighter requirement than C. http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap03.html#tag_03_244 http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/stddef.h.html#tag_13_47 > We use plain 0 for a null pointer constant in various > existing tests in configure; this is simpler and avoids > dragging in stddef.h. I would prefer that. I agree that configure tests should be as small as possible while still being correct, and use of a 0 constant without a cast, rather than NULL, is appropriate in that context. -- Eric Blake ebl...@redhat.com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
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