Re: [PATCH for-4.15 2/2] tools/xenstore: Check the format printf for xprintf() and barf{,_perror}()

[Jan Beulich <jbeulich@xxxxxxxx>]

On 05.03.2021 14:01, Jürgen Groß wrote:
> On 05.03.21 13:40, Julien Grall wrote:
>> From: Julien Grall <jgrall@xxxxxxxxxx>
>> --- a/tools/xenstore/utils.h
>> +++ b/tools/xenstore/utils.h
>> @@ -29,10 +29,12 @@ const char *dump_state_align(FILE *fp);
>>   
>>   #define PRINTF_ATTRIBUTE(a1, a2) __attribute__((format (printf, a1, a2)))
>>   
>> -void barf(const char *fmt, ...) __attribute__((noreturn));
>> -void barf_perror(const char *fmt, ...) __attribute__((noreturn));
>> +#define __noreturn __attribute__((noreturn))
>>   
>> -extern void (*xprintf)(const char *fmt, ...);
>> +void barf(const char *fmt, ...) __noreturn PRINTF_ATTRIBUTE(1, 2);
>> +void barf_perror(const char *fmt, ...) __noreturn PRINTF_ATTRIBUTE(1, 2);
>> +
>> +extern void (*xprintf)(const char *fmt, ...) PRINTF_ATTRIBUTE(1, 2);
> 
> ... the extern here would be dropped.

But this isn't a function declaration, but that of a data object.
With the extern dropped, a common symbol will appear in every CU.

Jan