On Mon, Nov 05, 2012 at 11:19:00PM +0900, Hitoshi Mitake wrote: > On Mon, Nov 5, 2012 at 11:04 PM, Thomas Preud'homme <[email protected]> wrote: > > Le lundi 5 novembre 2012 14:53:16, Hitoshi Mitake a écrit : > >> Of course, comparison between different typed structs or structs and > >> scalar typed values should cause compile error. But I feel that if we > >> can write comparison between same struct typed values with == > >> operator, a compiler will be very useful. Because we can avoid the > >> possibility of passing wrong value as 3rd parameter of memcmp(). > > > > memcmp is not what you want because if a structure contains padding you are > > not sure of its content. Therefore two structures could be identical with > > different content inside the padding. You must compare field by field. > > That's why > > assignement is possible but not equality: assignment is ok because you can > > copy the padding so memcpy will give a valid copy of the structure. > > Comparing > > with memcpy on the other hand will return false for some equal structures. > > Ah, I missed about the padding... As you say, memcmp() is not a stuff for the > above situation.
I had never thought of that, interesting edge case. > >> The standard of C doesn't allow this behaviour. But I think it may be > >> worth implementing it on TCC. Can TCC accept this behaviour as > >> implementation specific dialect? > > > > From http://bellard.org/tcc/ : > > > > UNLIMITED! Any C dynamic library can be used directly. TCC is heading > > torward > > full ISOC99 compliance. TCC can of course compile itself. > > > > I don't think we should not follow C99 on this. > > > > OK, I understand the direction of TCC. > I'll implement == for field by field comparison only for my toy if I'll do :) > > Thanks, Regardless, I'd be interested in seeing your branch of tcc if you have it hosted anywhere? Thanks, Rob _______________________________________________ Tinycc-devel mailing list [email protected] https://lists.nongnu.org/mailman/listinfo/tinycc-devel
