Re: [PATCH v5] elf: fixes compile error when both enable -Werror and -DNDEBUG

[Florian Weimer <fweimer@redhat.com>]

* Yang Yanchao:

> On 2022/4/15 15:36, Yang Yanchao wrote:
>> Use -Werror and -DNDEBUG at the same time will causes the following
>> compilation errors:
>> cache.c: In function 'save_cache':
>> cache.c:758:15: error: unused variable 'old_offset' [-Werror=unused-variable]
>>   758 |       off64_t old_offset = lseek64 (fd, extension_offset, SEEK_SET);
>>       |               ^~~~~~~~~~
>> -DNDEBUG will disables the assertion.
>> Therefore, only the variables used by assertions do not take effect.
>> use __attribute__ ((unused)) to disable this warning.
>> ---
>>  elf/cache.c | 3 ++-
>>  1 file changed, 2 insertions(+), 1 deletion(-)
>> diff --git a/elf/cache.c b/elf/cache.c index dbf4c83a7a..e92860023c
>> 100644
>> --- a/elf/cache.c
>> +++ b/elf/cache.c
>> @@ -754,7 +754,8 @@ save_cache (const char *cache_name)
>>    if (opt_format != opt_format_old)
>>      {
>>        /* Align file position to 4.  */
>> -      off64_t old_offset = lseek64 (fd, extension_offset, SEEK_SET);
>> +      __attribute__ ((unused)) off64_t old_offset
>> +        = lseek64 (fd, extension_offset, SEEK_SET);
>>        assert ((unsigned long long int) (extension_offset - old_offset) < 4);
>>        write_extensions (fd, str_offset, extension_offset);
>>      }
>> 
>
> ping again

Sorry for the delay.  I've reworded the commit message slightly and
pushed your change.

Thanks,
Florian