[PATCH 5/6] Cygwin: Fix warnings about narrowing conversions of socket ioctls

[Brian Inglis]

On 2024-08-11 12:31, Brian Inglis wrote:
> On 2024-08-07 08:06, Corinna Vinschen wrote:
>> On Aug  6 19:58, Jon Turney wrote:
>>> On 05/08/2024 11:22, Corinna Vinschen wrote:
>>>> On Aug  4 22:48, Jon Turney wrote:
>>>>> Fix gcc 12 warnings about narrowing conversions of socket ioctl constants
>>>>> when used as case labels, e.g:
>>>>> [...]
>>>> The only caller, fhandler_socket::ioctl, passes an unsigned int
>>>> value to get_ifconf. Given how the value is defined, it would be
>>>> more straightforward to convert get_ifconf to
>>>>
>>>>     get_ifconf (struct ifconf *ifc, unsigned int what);
>>>>
>>>> wouldn't it?
>>>
>>> Yeah, I'm not sure why I didn't do that.  I think I got confused about where
>>> this is used from.
> 
>> LGTM.  I will additionally push a patch dropping the useless casts.
> 
> Hi folks,
> 
> Trying to rebuild got a couple of issues with gcc12 and likely recent updates to 
> main, as my previous rebuild for /proc/cpuinfo with gcc11 was fine:
> 
> - picky g++
> 
>    CXX      net.o
> In file included from 
> /usr/src/newlib-cygwin/winsup/cygwin/include/cygwin/socket.h:47,
>                   from /usr/src/newlib-cygwin/winsup/cygwin/include/cygwin/if.h:17,
>                   from /usr/src/newlib-cygwin/winsup/cygwin/include/ifaddrs.h:42,
>                   from /usr/src/newlib-cygwin/winsup/cygwin/net.cc:26:
> /usr/src/newlib-cygwin/winsup/cygwin/net.cc: In function ‘int 
> get_ifconf(ifconf*, int)’:
> /usr/src/newlib-cygwin/winsup/cygwin/net.cc:1940:18: error: narrowing conversion 
> of ‘2152756069’ from ‘long unsigned int’ to ‘int’ [-Wnarrowing]
>   1940 |             case SIOCGIFFLAGS:
>        |                  ^~~~~~~~~~~~
> ... and so on
> 
> 50cf10dfa485 Cygwin: asm/socket.h: drop outdated casts
> 
> so change net.cc get_ifconf (struct ifconf *ifc, int what) to unsigned long, and 
> where it is also declared in fhandler/socket.cc?
> 
> - __utoa (and __itoa) declared in stdlib.h inside #ifndef __CYGWIN__
> 
>    CC       libc/stdlib/libc_a-itoa.o
> /usr/src/newlib-cygwin/newlib/libc/stdlib/itoa.c: In function ‘__itoa’:
> /usr/src/newlib-cygwin/newlib/libc/stdlib/itoa.c:57:3: warning: implicit 
> declaration of function ‘__utoa’; did you mean ‘__itoa’? 
> [-Wimplicit-function-declaration]
>     57 |   __utoa (uvalue, &str[i], base);
>        |   ^~~~~~
>        |   __itoa
> 
> 
> 31f7cd1e4332 Hide itoa, utoa, __itoa and __utoa in stdlib.h on Cygwin only
> 
> $ grep -C2 utoa ../../newlib/libc/include/stdlib.h
> #ifndef __CYGWIN__
> char *  __itoa (int, char *, int);
> char *  __utoa (unsigned, char *, int);
> # if __MISC_VISIBLE
> char *  itoa (int, char *, int);
> char *  utoa (unsigned, char *, int);
> # endif
> #endif
> 
> so should this be __INSIDE_CYGWIN__ instead or something else?

Sorry folks,

Did not notice patches 5-6/6 have not yet been applied.
Apply both okay and rebuild proceeding.

-- 
Take care. Thanks, Brian Inglis              Calgary, Alberta, Canada

La perfection est atteinte                   Perfection is achieved
non pas lorsqu'il n'y a plus rien à ajouter  not when there is no more to add
mais lorsqu'il n'y a plus rien à retirer     but when there is no more to cut
                                 -- Antoine de Saint-Exupéry