Re: [Qemu-devel] [PATCH] linux-user: Remove type casts to union type

[Stefan Weil <sw@weilnetz.de>]

Am 10.02.2015 um 20:51 schrieb Michael Tokarev:
> 08.02.2015 17:40, Stefan Weil wrote:
>> Casting to a union type is a gcc (and clang) extension. Other compilers
>> might not support it. This is not a problem today, but the type casts
>> can be removed easily. Smatch now no longer complains like before:
>>
>> linux-user/syscall.c:3190:18: warning: cast to non-scalar
>> linux-user/syscall.c:7348:44: warning: cast to non-scalar
>>
>> Cc: Riku Voipio <riku.voipio@iki.fi>
>> Signed-off-by: Stefan Weil <sw@weilnetz.de>
>> ---
>>  linux-user/syscall.c |   10 ++++++----
>>  1 file changed, 6 insertions(+), 4 deletions(-)
>>
>> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
>> index 852308e..ec137db 100644
>> --- a/linux-user/syscall.c
>> +++ b/linux-user/syscall.c
>> @@ -2663,8 +2663,9 @@ static inline abi_long host_to_target_semarray(int semid, abi_ulong target_addr,
>>  }
>>  
>>  static inline abi_long do_semctl(int semid, int semnum, int cmd,
>> -                                 union target_semun target_su)
>> +                                 abi_ulong target_arg)
>>  {
>> +    union target_semun target_su;
>>      union semun arg;
>>      struct semid_ds dsarg;
>>      unsigned short *array = NULL;
>> @@ -2673,6 +2674,8 @@ static inline abi_long do_semctl(int semid, int semnum, int cmd,
>>      abi_long err;
>>      cmd &= 0xff;
>>  
>> +    target_su.buf = target_arg;
> 
> 
> Can we use c99 initializers at declaration, something like
> 
>    union target_semun target_su = { .buf = target_arg }
> 
> ?  Or is it also some gcc/clang extension? :)
> 
> But I'd like to hear from Riku at least...
> 
> Thanks,
> 
> /mjt
> 

Ping. This patch is still missing.

Hello Michael,

using a c99 initializer is a good idea. We already have lots
of them, it's not a gcc extension but C standard.

Should I send an updated patch, or do you want to modify
the code before applying it?

Regards,
Stefan