[prev in list] [next in list] [prev in thread] [next in thread] 

List:       busybox
Subject:    Re: [PATCH 3/3] platform: fix missing sigisemptyset
From:       walter harms <wharms () bfs ! de>
Date:       2013-12-01 15:30:53
Message-ID: 529B562D.1040809 () bfs ! de
[Download RAW message or body]


mea culpa,
missread the code

re,
 wh

Am 27.11.2013 16:57, schrieb Daniel Borca:
> Walter,
> 
> First, there's no memcopy [sic] in that code.
> 
> Second, memcmp returns an int.
> 
> Third, even if there was a memcopy [sic] returning a pointer,
> you failed to notice the ! aka logical not.  Now, the result
> of !p (where p is a pointer) will not be a pointer.
> 
> http://c-faq.com/null/ptrtest.html and http://c-faq.com/bool/bool2.html
> 
> That is, !p will always be either 0 or 1, and. nothing. else.
> At least on any C compiler that's even slightly relevant.
> 
> walter harms wrote:
>>
>>
>> Am 27.11.2013 15:21, schrieb Denys Vlasenko:
>>> On Wed, Nov 27, 2013 at 2:46 AM, Rich Felker<dalias@aerifal.cx>  wrote:
>>>> On Tue, Nov 26, 2013 at 10:01:36PM +0200, Daniel Borca wrote:
>>>>> +#ifndef HAVE_SIGISEMPTYSET
>>>>> +int sigisemptyset(sigset_t *set)
>>>>> +{
>>>>> +     sigset_t empty;
>>>>> +     int ret = sigemptyset(&empty);
>>>>> +     if (ret == 0) {
>>>>> +             ret = !memcmp(&empty, set, sizeof(sigset_t));
>>>>> +     }
>>>>> +     return ret;
>>>>> +}
>>>>> +#endif
>>>>
>>>> This is not a suitable fallback implementation. It's not needed on
>>>> musl (we provide sigisemptyset), but if this version were used, it
>>>> would give the wrong results, because musl's sigemptyset only fills
>>>> the first _NSIG-1 bits and ignores the remaining ~900 bits of junk in
>>>> sigset_t.
>>>
>>> Why does musl use such pointlessly huge sigset_t?
>>
>>
>> i would expect a warning here. ret is int and memcopy returns (void *).
>> This makes int=void*.
>>
>> re,
>>   wh
> 
> -dborca
> 
_______________________________________________
busybox mailing list
busybox@busybox.net
http://lists.busybox.net/mailman/listinfo/busybox
[prev in list] [next in list] [prev in thread] [next in thread]