On 18 Feb 2011, at 13:12, Black, Michael (IS) wrote:
> I'm of the opinion that all such warnings should be permanently fixed. Such
> warnings do point to potential problems.
> And not by disabling the warning but by fixing the code (explicit casts for
> example).
It's been a while since I last did multiplatform C development, but in 2005 I
found that MSVC and the HP-UX compiler were always brilliant at pointing out
'problems' which almost never mattered while missing severe (crash-causing)
issues which were found by IBM's xlc, GNU GCC and clang.
> How many people try this and get worried about possible problems? If you
> simply fix the code once all those people will feel a whole lot better when
> they crank up the warnings and see nothing.
There are plenty of cases which cause a warning from one compiler but if
'fixed' in the obvious way will cause another warning from a different
compiler: it becomes a case of whose warnings you want to get rid of.
> I went through this exercise myself for SQLite at one point and looked at
> each and every warning to try and determine if there was a possible error
> caused by all the miscasts.
Adding casts to get rid of warnings is usually the wrong answer in my
experience. Certainly you should never cast the return value of a function call
because that hides the problems you get when it's implicitly returning int
because a required header is missing. I used to see a lot of C code (usually
from Windows programmers - does MSVC encourage this?) which has stuff like this
all over the place:
struct something *fred = (struct something *)malloc(sizeof(struct
something));
Casting the return from malloc is never necessary - void * is assignable to any
non-function pointer type by definition.
It becomes an extremely bad idea when you're building on a platform with 64-bit
pointers and a 32-bit int (such as everything I use) and you have the optimiser
turned on – in this case if <stdlib.h> isn't included none of your allocations
will work properly and your program will crash.
Best Regards,
Phil Willoughby
--
Managing Director, StrawberryCat Limited
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