Re: Being more anal about iospace accesses..
From: Brian Gerst
Date: Wed Sep 15 2004 - 12:49:12 EST
Jörn Engel wrote:
On Wed, 15 September 2004 09:30:42 -0700, Linus Torvalds wrote:
For example, if you don't know (or, more importantly - don't care) what
kind of IO interface you use, you can now do something like
void __iomem * map = pci_iomap(dev, bar, maxbytes);
...
status = ioread32(map + DRIVER_STATUS_OFFSET);
C now supports pointer arithmetic with void*? I hope the width of a
void is not architecture dependent, that would introduce more subtle
bugs.
Jörn
http://gcc.gnu.org/onlinedocs/gcc-3.4.2/gcc/Pointer-Arith.html#Pointer-Arith
5.18 Arithmetic on void- and Function-Pointers
In GNU C, addition and subtraction operations are supported on pointers
to void and on pointers to functions. This is done by treating the size
of a void or of a function as 1.
A consequence of this is that sizeof is also allowed on void and on
function types, and returns 1.
The option -Wpointer-arith requests a warning if these extensions are used.
--
Brian Gerst
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