potentially incorrect conversion of pointer to unsigned long
cs at cskk.id.au
Sat Jun 22 23:01:43 UTC 2019
On 22Jun2019 21:14, vincent lefevre <vincent at vinc17.org> wrote:
>On 2019-06-22 12:40:39 +0200, Oswald Buddenhagen wrote:
>> On Sat, Jun 22, 2019 at 09:42:36AM +0200, Vincent Lefevre wrote:
>> > p->init = (unsigned long) safe_strdup (* ((char **) p->data));
>> > IMHO, the best solution for safety would be to use a union (I think
>> > that this would require the use of C99 designators for the MuttVars
>> > initialization). Otherwise check (uintptr_t) -1 <= (unsigned long) -1
>> > in configure.
>> it's easier to just use !! or put != NULL at the end instead of the cast.
>AFAIK, the value itself matters, not just the fact that it is
If I were doing this in Python or any other object oriented language I'd
have a special sentinel value of the right type i.e. _not_ some magic -1
value we expect to not match any other pointer-as-integer value and also
not NULL, but an actual distinct special purpose (char*).
So how about this:
#define UNSET_CHAR_PTR "<unset>"
and to use UNSET_CHAR_PTR instead of (uintptr_t)-1 and (unsigned
Specificly, this way we (a) avoid doing any casts and (b) avoid any need
for a union and its associated cognitive dissonance and (c) avoid a
magic number in the code (the -1, in whatever form).
I'm totally serious about this, BTW.
Cameron Simpson <cs at cskk.id.au>
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