Re: win32 random number generator
- From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
- To: "Merlin Moncure" <merlin(dot)moncure(at)rcsonline(dot)com>
- Cc: pgsql-hackers-win32(at)postgresql(dot)org
- Subject: Re: win32 random number generator
- Date: Mon, 22 Aug 2005 17:32:39 -0400
- Message-id: <21425(dot)1124746359(at)sss(dot)pgh(dot)pa(dot)us>
"Merlin Moncure" <merlin(dot)moncure(at)rcsonline(dot)com> writes:
> Looks like this in lrand48(void):
> //return ((long) _rand48_seed[2] << 15) + ((long) _rand48_seed[1] > 1);
> is supposed to be this:
> return (long)((unsigned long) _rand48_seed[2] << 15) + ((unsigned long)
> _rand48_seed[1] >> 1);
Hmm, _rand48_seed is unsigned short, so casting to either long or
unsigned long should zero-extend, and then it doesn't matter whether
the shifts think it's signed or not. In short, that shouldn't change
the behavior unless your compiler is broken.
regards, tom lane
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