Fwd: Re: [PATCH 1/1] include/basetsd.h: fix bad casting
On 10/12/2012 10:25 PM, Dan Kegel wrote:
Hi Max, here's a little test program that shows that your patch changes how UIntToPtr works:
#include <stdio.h> #include <stdint.h>
#define UIntToPtrA(i) ((void *)(intptr_t)((unsigned int)i)) #define UIntToPtrB(i) ((void *)(intptr_t)(i))
int main(int argc, char **argv) { short x = 65534; printf("%d -> %p\n", x, UIntToPtrA(x)); printf("%d -> %p\n", x, UIntToPtrB(x)); return 0; }
On a 64 bit machine, this outputs
-2 -> 0xfffffffe -2 -> 0xfffffffffffffffe
This could change the behavior of functions that call UIntToPtr, like say EnumResourceTypesA().
I would suggest writing a conformance test to expose whether the change brings Wine closer to native behavior, or further away, adding that to your patch, and then verifying with winetestbot that the patch improves wine's conformance.
My guess is that the current behavior is right, but hey, the test will show what's really up. - Dan
I 'greped' the entire wine tree for uses of these macros. There was only a couple places where the argument was an expression and in those cases I did not see that the change would cause problems. Frankly, I do not think I could come up with a test where the change would make a difference. I am submitting the patch against the weird possibility that such a case does exist. The change is strictly preventative maintenance with just a hint of aesthetic improvement to make them coordinate with the 'Handle' variants of these macros. Now, if you are going to tell me that these definitions were *copied* from a Microsoft *source* rather than derived from a Microsoft specification, you would have a point, but then there would be a whole bunch of copyright issues that would need to be worked through.
Max TenEyck Woodbury <max(a)mtew.isa-geek.net> writes:
Now, if you are going to tell me that these definitions were *copied* from a Microsoft *source* rather than derived from a Microsoft specification, you would have a point, but then there would be a whole bunch of copyright issues that would need to be worked through.
You can't copyright a typecast, and yes, the macros are broken the same way in the Microsoft headers, we are just being compatible. -- Alexandre Julliard julliard(a)winehq.org
On 10/13/2012 09:14 AM, Alexandre Julliard wrote:
Max TenEyck Woodbury <max(a)mtew.isa-geek.net> writes:
Now, if you are going to tell me that these definitions were *copied* from a Microsoft *source* rather than derived from a Microsoft specification, you would have a point, but then there would be a whole bunch of copyright issues that would need to be worked through.
You can't copyright a typecast, and yes, the macros are broken the same way in the Microsoft headers, we are just being compatible.
Ah, but you CAN copyright a MISTAKE! Especially if it was introduced deliberately for the sake of catching copyright infringers. Since it is gratuitous, like a grace note in a musical score, it can be used to show the code was actually copied rather than being something needed to implement the uncopyrightable idea in a specification. Please apply the change. If you have any doubts, check with a *copyright* lawyer. Reference the recent Oracle vs Google case.
participants (2)
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Alexandre Julliard -
Max TenEyck Woodbury