Re: free() and implicit conversion to a function pointer

[Eric Blake <eblake@redhat.com>]

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On 03/16/2017 02:24 PM, Hans-Bernhard Bröker wrote:
> 
> The reason this is wrong is that C by design treats data and functions
> as living in separate realms, i.e. its virtual machine has a Harvard
> architecture.  One of the consequences of this is that pointers to
> functions and pointers to data are incommensurable, i.e. any and all
> conversions or comparisons across this divide are wrong.  (void *) are
> compatible to all data pointers, but not to function pointers.

That's true of strict C99, but not true of POSIX (which adds the
additional requirements above-and-beyond C99 that NULL be equivalent to
((void*)0) and that any function pointer can be converted to void* and
back without loss of information, in part because of dlsym() and friends).

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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