Date: Wed, 20 Jun 2001 21:03:47 +0300
From: "Eli Zaretskii" <eliz AT is DOT elta DOT co DOT il>
Sender: halo1 AT zahav DOT net DOT il
To: Martin Str|mberg <ams AT ludd DOT luth DOT se>
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In-reply-to: <200106201703.TAA22756@father.ludd.luth.se> (message from Martin
	Str|mberg on Wed, 20 Jun 2001 19:03:03 +0200 (MET DST))
Subject: Re: Casting left side to unsigned or right side to signed?
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> From: Martin Str|mberg <ams AT ludd DOT luth DOT se>
> Date: Wed, 20 Jun 2001 19:03:03 +0200 (MET DST)
> 
>    else if (header[0] == 0x5a4d)        /* "MZ" */
>    {
>      char go32stub[9];
> -    unsigned long coff_start = (unsigned long)header[2]*512L;
> -    unsigned long exe_start;
> -    unsigned long real_exe_start;
> +    off_t coff_start = header[2]*512L;
> +    off_t exe_start;
> +    off_t real_exe_start;
>      type.exec_format = _V2_EXEC_FORMAT_EXE;
> 
> Should I keep the cast here too?

I'm paranoiac about promotion from unsigned short to signed int (off_t
is signed), so I would keep the cast.  But perhaps people who are more
sure in what C mandates than I am will have different advice ;-)

> 2. If we decided to do the cast (theoretically speaking) which way is
> best to cast? signed -> unsigned or unsigned -> signed?

If you know that the value is non-negative, then signed->unsigned is
safer.