svn commit: r303988 - head/lib/libc/gen

[Eric van Gyzen]

On 08/24/2016 15:16, Bryan Drewery wrote:
> On 8/24/16 1:12 PM, Eric van Gyzen wrote:
>> On 08/24/2016 15:01, Ed Schouten wrote:
>>> 2016-08-24 21:53 GMT+02:00 Bryan Drewery <bdrewery at freebsd.org>:
>>>> Is it possible to cause the use of these old prototypes to print a
>>>> warning and note that they are deprecated/unsafe?
>>>
>>> That's a good question. In theory, we could annotate these functions
>>> with __attribute__((__deprecated__)):
>>>
>>> https://gcc.gnu.org/onlinedocs/gcc-3.3.4/gcc/Type-Attributes.html
>>>
>>> But I'm actually too afraid to use it. In the worst case it may cause
>>> the compiler to generate a warning even when basename()/dirname() is
>>> used correctly, as __old_* will still be part of the compiled
>>> expression.
>>
>> Could __warn_references() be used, as libc currently does for gets() and
>> others?
>>
>> Eric
>>
> 
> /usr/include/stdio.h:extern char *gets (char *__s) __wur
> __attribute_deprecated__;
> /usr/include/x86_64-linux-gnu/sys/cdefs.h:# define
> __attribute_deprecated__ __attribute__ ((__deprecated__))
> 
> __wur being warning about unused result.

/usr/src/lib/libc/stdio/gets.c:__warn_references(gets, "warning: this
program uses gets(), which is unsafe.");

> As for actually using it here, I tried adding it onto the
> _old_dirname/basename prototypes.  It produces an error, fine, in the
> bootstrap build for xinstall it would not error, great.  However, for
> building xinstall on head where it will not use the __old_dirname and
> will use the new dirname at FBSD_1.5, it _still_ complains about using the
> __old_dirname() prototype via __generic and errors in the wrong case.