Re: [dpdk-dev] [PATCH 3/3 v2] librte_eal/common: Fix redeclaration of enumerator ‘REG_EAX’

["Qiu, Michael" <michael.qiu@intel.com>]

On 2015/3/5 22:39, Thomas Monjalon wrote:
> 2015-03-05 14:03, Qiu, Michael:
>> On 3/5/2015 9:54 PM, David Marchand wrote:
>>> On Thu, Mar 5, 2015 at 2:50 PM, Michael Qiu <michael.qiu@intel.com
>>> <mailto:michael.qiu@intel.com>> wrote:
>>>
>>>     include/rte_cpuflags.h:154:2: error: redeclaration of enumerator
>>>     ‘REG_EAX’
>>>     In file included from /usr/include/signal.h:358:0,
>>>                      from /usr/include/sys/wait.h:30,
>>>                      from /root/dpdk/app/test/test_mp_secondary.c:50:
>>>     /usr/include/sys/ucontext.h:180:3: note: previous definition of
>>>     ‘REG_EAX’ was here
>>>
>>>     In i686, from REG_EAX to REG_EDX are all defined in
>>>             /usr/include/sys/ucontext.h
>>>
>>>     Rename to CPU_REG_EAX to avoid this issue.
>>>
>>>     Signed-off-by: Michael Qou <michael.qiu@intel.com
>>>     <mailto:michael.qiu@intel.com>>
>>>
>>>
>>> NAK.
>>>
>> I have answered in you last thread, please check the mail.
>>
>> Yes, but for some reason, it was not include, see /usr/include/signal.h:358
>>
>> # include <bits/sigstack.h>
>> # if defined __USE_XOPEN || defined __USE_XOPEN2K8
>> /* This will define `ucontext_t' and `mcontext_t'.  */
>> #  include <sys/ucontext.h>
>> # endif
>>
>> So only if __USE_XOPEN or __USE_XOPEN2K8 been defined will include 
>> <sys/ucontext.h>
> So try to define USE_XOPEN.
>
>> Why NAK?
> Because it seems you didn't really try to include system headers.

See below(ucontext.h:25):
#ifdef __x86_64__
...
#ifdef __USE_GNU
enmu{
    ...
  REG_RBX,
# define REG_RBX        REG_RBX
  REG_RDX,
# define REG_RDX        REG_RDX
  REG_RAX,
# define REG_RAX        REG_RAX
  REG_RCX,
# define REG_RCX        REG_RCX
...
};
#endif
...
#else /* !__x86_64__ */
...
#ifdef __USE_GNU
enmu{
...
  REG_EBX,
# define REG_EBX        REG_EBX
  REG_EDX,
# define REG_EDX        REG_EDX
  REG_ECX,
# define REG_ECX        REG_ECX
  REG_EAX,
# define REG_EAX        REG_EAX
...
};
#endif
...
#endif /* !__x86_64__ */


For none x86_64 platform will be defined as REG_E*X, but x86_64 will be
REG_R*X.

This is why only happens in i686 platform.

Does this clear?

Thanks,
Michael
> We must avoid redefine existing symbols. That's why this bug happens.
> Michael, thanks for trying to fix this issue. It's appreciated even if
> the first solution is refused.
>
>