Re: [Qemu-devel] [PATCH] osdep: pass const char pointer to setsockopt

[Lei Li <lilei@linux.vnet.ibm.com>]

On 03/06/2013 09:16 PM, Stefan Hajnoczi wrote:
> On Wed, Mar 06, 2013 at 09:07:25PM +0800, Lei Li wrote:
>> On 03/06/2013 05:56 PM, Stefan Hajnoczi wrote:
>>> On Tue, Mar 05, 2013 at 05:51:21PM +0800, Lei Li wrote:
>>>> Pass the right type for setsockopt(), and this will also
>>>> fix the compiler warning when cross build for qemu-ga.exe:
>>>>
>>>> util/osdep.c: In function 'socket_set_nodelay':
>>>> util/osdep.c:69:5: warning: passing argument 4 of 'setsockopt' from
>>>>                     incompatible pointer type [enabled by default]
>>>> In file included from /home/lei/qemu_b/include/sysemu/os-win32.h:30:0,
>>>>                   from /home/lei/qemu_b/include/qemu-common.h:46,
>>>>                   from util/osdep.c:48:
>>>> /usr/i686-w64-mingw32/sys-root/mingw/include/winsock2.h:990:63: note:
>>>>                   expected 'const char *' but argument is of type 'int *'
>>>>
>>>> Signed-off-by: Lei Li <lilei@linux.vnet.ibm.com>
>>>> ---
>>>>   util/osdep.c | 4 ++--
>>>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/util/osdep.c b/util/osdep.c
>>>> index c408261..ce472a9 100644
>>>> --- a/util/osdep.c
>>>> +++ b/util/osdep.c
>>>> @@ -57,7 +57,7 @@ static const char *qemu_version = QEMU_VERSION;
>>>>   int socket_set_cork(int fd, int v)
>>>>   {
>>>>   #if defined(SOL_TCP) && defined(TCP_CORK)
>>>> -    return setsockopt(fd, SOL_TCP, TCP_CORK, &v, sizeof(v));
>>>> +    return setsockopt(fd, SOL_TCP, TCP_CORK, (char *)&v, sizeof(v));
>>>>   #else
>>>>       return 0;
>>>>   #endif
>>>> @@ -66,7 +66,7 @@ int socket_set_cork(int fd, int v)
>>>>   int socket_set_nodelay(int fd)
>>>>   {
>>>>       int v = 1;
>>>> -    return setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &v, sizeof(v));
>>>> +    return setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, (char *)&v, sizeof(v));
>>> Please use qemu_setsockopt() instead of open-coding this.
>>>
>>> Stefan
>>>
>> Hi Stefan,
>>
>> This compiler warning just shows up without any hacking
>> when cross build qemu-ga for windows by:
>>
>> ./configure --enable-guest-agent --cross-prefix=i686-w64-mingw32-
>> make qemu-ga.exe
> I understand you didn't introduce the bug and noticed it when compiling
> for Windows.
>
> The correct fix is still to use qemu_setsockopt() which was added in
> order to solve this portability problem.
>
> You don't need any casts if you use qemu_setsockopt().
>
> Stefan

Sorry, I understand it just now...  :-[
Sure, thanks!



-- 
Lei