On Mon, Sep 02, 2013 at 10:55:55PM +0200, Jakub Hrozek wrote: > On Mon, Sep 02, 2013 at 03:20:12PM -0400, Simo Sorce wrote: > > On Mon, 2013-09-02 at 19:18 +0200, Lukas Slebodnik wrote: > > > ehlo, > > > > > > Some platforms can have defined SIZE_T_MAX. > > > It is better to use conditional build. > > > > > > Two patches are attached. one for master(1.10) and second for 1.9 > > > > > > Uhmm defining SIZE_T_MAX as (size_t)-1 is not technically correct, it > > may work with gcc, but could fail with an optimizer, as -1 is simply an > > illegal value for an unsigned quantity. > > > > We should use the actual maximum value here. > > > > Simo. > > tl;dr - I think we should simply use SIZE_MAX instead. > > I actually think Lukas' patch *improves* the code. It seems that the > non-patched code defined SIZE_T_MAX no matter what. Lukas simply wraps > the macro #define in an #ifdef so if a platform defined SIZE_T_MAX in > some kind of system wide header, the definition would be picked up. > > But the real question I see is why did we ever use SIZE_T_MAX where we > should have used SIZE_MAX ? The standard says (7.18.3) that size_t > maximum value is SIZE_MAX with the minimum value set to 65535 where > implementations can choose larger values.
I think using SIZE_MAX is a good idea here since the standard defines it as the limit of size_t. I introduced SIZE_T_MAX to check for overflows on variables of type size_t. So even if the implementation does not choose to change 65535 to the actual maximal value of size_t the checks will still work, but will limit to corresponding operations to 16bits although more might be possible. bye, Sumit > > Also, what problem do you see with (size_t)-1 ? As far as I see, this > is the recommended approach. The only alternative I can think of is ~0 > but in several discussions (on comp.lang.c.moderated) this was considered > unsafe on some machines. > _______________________________________________ > sssd-devel mailing list > [email protected] > https://lists.fedorahosted.org/mailman/listinfo/sssd-devel _______________________________________________ sssd-devel mailing list [email protected] https://lists.fedorahosted.org/mailman/listinfo/sssd-devel
