On Thu, 31 Jul 1997, Peter Gerwinski wrote:

According to Bill Currie:

...

I'VE FIXED IT!! The problem was caused by a negative index into the hash table.

Congratulations and thank you!

...

To fix it change the line (gci-hash.c:122):

(((((char *)(NODE))-(char *)0) >> 2) % MAX_HASH_TABLE)

to:

(((((unsigned long)(NODE))-(unsigned long)0) >> 2) % MAX_HASH_TABLE)

Since pointers and `long' integers don't have the same size on some sytems (I know it for the Alpha), I think this should be changed to something like `(unsigned size_t)'.

Peter,

In the alpha:

sizeof(long) == sizeof(void *) sizeof(int) != sizeof(void *)

Quickly thinking, in all Unix machines it might be that sizeof(long) == sizeof (void *). But this just might not always be the case, so it can not be trusted.

In ANSI C the result of (ptr - ptr) is of type ptrdiff_t, which in the alpha is (signed long).

Using cast (unsigned size_t) might not be a good idea, at least I do not know if Ansi C quarantees that size_t always is as large as ptrdiff_t.

I suggest that this problem is fixed by casting the result of the pointer subtraction to (unsigned ptrdiff_t) which is always large enough, something like:

(((unsigned ptrdiff_t)(((char *)(NODE))-(char *)0) >> 2) % MAX_HASH_TABLE)

Juki jtv@hut.fi