Clang: Replacing __attribute((__warning__())) by __attribute__((deprecated()))

[Olivier MARTIN]

Sorry, I forgot to mention but the issue is related to these invocations 
in newlib/libc/include/stdlib.h such as:
char * _EXFUN(mktemp,(char *) _ATTRIBUTE ((__warning__ ("the use of 
`mktemp' is dangerous; use `mkstemp' instead"))));

The Clang warning message is:
char * _EXFUN(mktemp,(char *) _ATTRIBUTE ((__warning__ ("the use of 
`mktemp' is dangerous; use `mkstemp' instead"))));

/home/olivier/Toolchains/gcc-arm-none-eabi-4_9-2014q4/arm-none-eabi/include/stdlib.h:114:44: 
warning: unknown attribute '__warning__' ignored
       [-Wunknown-attributes]
char *  _EXFUN(mktemp,(char *) _ATTRIBUTE ((__warning__ ("the use of 
`mktemp' is dangerous; use `mkstemp' instead"))));
                                             ^
/home/olivier/Toolchains/gcc-arm-none-eabi-4_9-2014q4/arm-none-eabi/include/_ansi.h:101:42: 
note: expanded from macro '_ATTRIBUTE'
#define _ATTRIBUTE(attrs) __attribute__ (attrs)
                                          ^
/home/olivier/Toolchains/gcc-arm-none-eabi-4_9-2014q4/arm-none-eabi/include/_ansi.h:65:35: 
note: expanded from macro '_EXFUN'
#define _EXFUN(name, proto)             name proto
                                              ^


On 25.10.2015 18:31, Olivier MARTIN wrote:
> Clang does not support the function attribute __warning__(), it raises
> the warning message: "warning: unknown attribute '__warning__'
> ignored"
> A solution would be to replace the attribute __warning__() by 
> deprecated().
> 
> Here is the GCC & Clang behaviour with some function attributes:
> 
> # The source code:
> ----------------------------
> void func1(void) __attribute__((__warning__ ("the use of `func1' is
> dangerous; use `funcN' instead")));
> void func2(void) __attribute__((deprecated("Deprecated func2; use
> `funcN` instead")));
> void func3(void) __attribute__((warning("the use of `func3' is
> dangerous; use `funcN' instead")));
> 
> int main(void) {
>   func1();
>   func2();
>   func3();
>   return 0;
> }
> ---------------------------
> 
> # With GCC:
> ---------------------------
> mytest.c: In function ‘main’:
> mytest.c:7:3: warning: ‘func2’ is deprecated (declared at mytest.c:2):
> Deprecated func2; use `funcN` instead [-Wdeprecated-declarations]
>    func2();
>    ^
> mytest.c:6:8: warning: call to ‘func1’ declared with attribute
> warning: the use of `func1' is dangerous; use `funcN' instead [enabled
> by default]
>    func1();
>         ^
> mytest.c:8:8: warning: call to ‘func3’ declared with attribute
> warning: the use of `func3' is dangerous; use `funcN' instead [enabled
> by default]
>    func3();
> ---------------------------
> 
> # With Clang:
> ---------------------------
> mytest.c:1:33: warning: unknown attribute '__warning__' ignored
> [-Wunknown-attributes]
> void func1(void) __attribute__((__warning__ ("the use of `func1' is
> dangerous; use `funcN' instead")));
>                                 ^
> mytest.c:3:33: warning: unknown attribute 'warning' ignored
> [-Wunknown-attributes]
> void func3(void) __attribute__((warning("the use of `func3' is
> dangerous; use `funcN' instead")));
>                                 ^
> mytest.c:7:3: warning: 'func2' is deprecated: Deprecated func2; use
> `funcN` instead [-Wdeprecated-declarations]
>   func2();
>   ^
> mytest.c:2:6: note: 'func2' has been explicitly marked deprecated here
> void func2(void) __attribute__((deprecated("Deprecated func2; use
> `funcN` instead")));
>      ^
> 3 warnings generated.
> ---------------------------
> 
> Here is the list of the function attributes supported by clang:
> - http://clang.llvm.org/docs/LanguageExtensions.html
> - http://clang.llvm.org/docs/AttributeReference.html
> 
> Are you happy by my suggestion of replacing
> __attribute((__warning__())) by __attribute__((deprecated()))?
> I am happy to send a patch if needed.
> Thanks,

-- 
Olivier MARTIN
http://labapart.com