This is the mail archive of the libc-alpha@sourceware.org mailing list for the glibc project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [PATCH v4] fix warnings in sys/select.h fortification with -Wsign-conversion


On Saturday 09 June 2012 16:24:14 Paul Eggert wrote:
> On 06/09/2012 11:55 AM, Mike Frysinger wrote:
> > in all cases where this is used, trying to use a pointer will trigger a
> > build failure.
> 
> True, but that's brittle, as it depends on some other internal macro
> having certain properties, and these properties aren't documented.
> And even if it works with pointers, it will fail in other cases.
> For example, the cast will cause diagnostics to be suppressed for
> FD_ISSET (4294967296, s) on a 32-bit machine, even though there
> should be a diagnostic.

yes, these are all valid cases (as i mentioned), but still fairly minor 
overall

> >> Paul came up with a better patch, which doesn't have this
> >> problem, and I propose that it be installed instead.
> > 
> > it has slightly more overhead
> 
> Not for any modern compiler with normal optimization;
> they all turn (0 <= x && x < CONSTANT) into a single
> unsigned comparison, even if x is signed.

as long as that's true, i'm fine going with Paul's latest version
-mike

Attachment: signature.asc
Description: This is a digitally signed message part.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]