Re: False positive in skalibs system feature test

From: Jens Rehsack <rehsack_at_gmail.com>
Date: Fri, 25 Oct 2019 22:01:02 +0200

> Am 25.10.2019 um 21:35 schrieb Guillermo <gdiazhartusch_at_gmail.com>:
>
> El vie., 25 oct. 2019 a las 14:30, Shengjing Zhu escribió:
>>
>> Not familiar with autoconf, but I found the following snippet in autoconf code.
>>
>> https://git.savannah.gnu.org/cgit/autoconf.git/tree/lib/autoconf/c.m4?h=v2.69#n179
>>
>> ```
>> #if defined __stub_$1 || defined __stub___$1
>> choke me
>> #endif
>
> This seems to be indeed what Autoconf currently uses when the
> AC_CHECK_FUNC macro is used to check if a function is available. The
> __stub_* macros are in <gnu/stubs.h> (which on my Gentoo x86_64 system
> includes <gnu/stubs-64.h>), an autogenerated GNU libc header included
> by <features.h>. I tried this with getrandom(), which exists, and
> lchmod(), which is a libc stub. Here are the results:

Taken from config.log ...
That is my argument for using autoconf. It tells you explicitly
each step it does and what went wrong. No need to guess.

> [...]
> configure:2634: result: no
>
> As you can see, only the equivalent of a skarnet.org 'choose cl' is used here.

Wasn't that clear enough when I told that weeks before?
For any typical library function, that is enough. Any exception is
broken by design (maybe for good reason, but anyway).

And - isn't clear how LibreSSL checks for getrandom() availability?
Please tell me, then I explain it in more details.

Cheers
--
Jens Rehsack - rehsack_at_gmail.com



Received on Fri Oct 25 2019 - 20:01:02 UTC

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