Chris Demetriou, who maintains the NetBSD DEC Alpha port, reported a problem in localtime.c's detzcode() function that occurs because the value being extracted from the string in that function is not sign extended properly.

He says: The problem is that if you do what the current version does, then you can end up with numbers like 0xffffyyyy being returned from detzcode(), i.e. no sign extension into the upper 32 bits of the long. Because of this, among other things, 'date' will say that it's some time in the year 2025...

Using the following detzcode() implementation (which unrolls the loop and doesn't mask the first character) works, but it suffers from a small defect in that it assumes signed characters.

static long detzcode(codep) const char * const codep; { register long result;

result = (codep[0] << 24) \ | (codep[1] & 0xff) << 16 \ | (codep[2] & 0xff) << 8 | (codep[3] & 0xff); return result; }

casting codep[0] to signed char would fix that, but would require a ANSI compiler.

How about this simple change? *** tz95b/localtime.c Sat Mar 4 11:22:26 1995 --- localtime.c Fri Mar 10 08:51:53 1995 *************** *** 186,200 **** static long detzcode(codep) const char * const codep; { register long result; register int i; ! result = 0; for (i = 0; i < 4; ++i) result = (result << 8) | (codep[i] & 0xff); return result; } static void settzname P((void)) --- 186,200 ---- static long detzcode(codep) const char * const codep; { register long result; register int i; ! result = ~0; for (i = 0; i < 4; ++i) result = (result << 8) | (codep[i] & 0xff); return result; } static void settzname P((void))