Quoting Christian Biere <[EMAIL PROTECTED]> from ml.softs.gtk-gnutella.devel: :Then what is the purpose of checking 'lid'? It seems pmi->nl can actually :be a dangling pointer and this is the point of the check. The code could :be made standard compliant by using pmi->lid instead of pmi->nl because :'lid' already maps to either 'nl' or NULL. Likewise, 'nl' could be carried :around as an integer instead of a pointer. Admittedly, a GarbageHashTable :defeats this by casting it back to a pointer - if you use that directly :as key - which you don't have to.
I perfectly know I'm handling a possibly dangling pointer value, and this is the purpose of the hash table. I know I could have used an ID in the table, but as it is a running count it would have meant using a 64-bit ID and that would imply the use of 64-bit atoms, and I don't want that. But let's face it: this code works fine as it is. An implementation of a C compiler that would put a level of indirection to all pointer accesses just to prevent using a pointer that has been freed would be braindead. Otherwise, if one handles the actual pointer value not like a pointer but as any normal integer quantity, then it is perfectly safe. Show me a C compiler that breaks that behaviour, i.e. which breaks the logic of lookup_is_alive(). :> Also, these pointers are always allocated as far as the implementation :> goes because they were allocated through malloc() underneath. The walloc() :> layer on top of that merely redistributes the allocated space among objects, :> but the space is not really freed. None of this memory is really freed. : :A very poor excuse. walloc() is supposed to be transparent to malloc() and :you can compile gtk-gnutella so that it uses malloc() all the time. In :fact for debugging that's highly recommended and by not adhereing to :the standard you make just this more difficult. Again, that would be Crappy, not C. Now if I were to dereference a dangling pointer, that would be a severe bug and it would warrant an immediate fix. Raphael P.S: Actually, that particular logic is older than you would think. And it has been running just fine for the past 4 years in gtk-gnutella already. Just look at dq_alive(). ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ gtk-gnutella-devel mailing list gtk-gnutella-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/gtk-gnutella-devel
