Re: 0xdeadbeef vs 0xdeadbeefL

[H. Peter Anvin]

Followup to:  <orn02cqs3u.fsf@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
By author:    Alexandre Oliva <aoliva@xxxxxxxxxx>
In newsgroup: linux.dev.kernel
>
> On Jul  6, 2004, Ray Lee <ray-lk@xxxxxxxxxxxxx> wrote:
> 
> > Which means 0xdeadbeef is a perfectly valid literal for an unsigned int.
> 
> Assuming ints are 32-bits wide.  They don't have to be.  They could be
> as narrow as 16 bits, in which case the constant will have type long
> or unsigned long (because long must be at least 32 bits), or they
> could be wider than 32 bits, in which case the constant will be signed
> int instead of unsigned int.  You might lose either way.  It's
> probably safer to make it explicitly UL, except perhaps in
> machine-specific files where the width of types is well-known.
> 

If it runs Linux:

	CHAR_BIT == 8
	sizeof(int) == 4
	sizeof(void(*)()) == sizeof(void *)
	sizeof(long) == sizeof(void *)
	sizeof(long long) == 8
	(long)NULL == 0L

These assumptions are pretty ingrained in the Linux kernel.
	
	-hpa
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/