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On 30/08/16 00:20, David Sommerseth wrote:
> On 29/08/16 23:32, Steffan Karger wrote:
>> HI,
>
>> On 29 August 2016 at 23:03, David Sommerseth
>> <open...@sf.lists.topphemmelig.net> wrote:
>>> On 29/08/16 22:45, David Sommerseth wrote:
>>>> On 28/08/16 21:42, Steffan Karger wrote:
>>>>> Previously, we would use the compiler's default C version,
>>>>> which defaults to gnu89 for GCC < 5, gnu11 for GCC > 5,
>>>>> and c11 for clang, but might even differ per distro.
>>>>
>>>>> One of the reasons to accept the gnu89 default of GCC <
>>>>> 4.9, was that MSVC didn't support c99. But in MSVC 2015,
>>>>> MS finanally fixed that.
>>>>
>>>>> Having to support c89 in the codebase occasionally forces
>>>>> us to write less readable code, for example by forcing all
>>>>> declaration to be at the starting of a block (which
>>>>> includes 'for loop initial declarations').
>>>>
>>>>> Let's be clear about what standard we obey, and stop
>>>>> punishing ourselves with c89/gnu89. Let's switch the
>>>>> master branch to c99.
>>>>
>>>>> Signed-off-by: Steffan Karger <stef...@karger.me> ---
>>>>> configure.ac | 1 + 1 file changed, 1 insertion(+)
>>>>
>>>>> diff --git a/configure.ac b/configure.ac index
>>>>> 9189c94..16cab19 100644 --- a/configure.ac +++
>>>>> b/configure.ac @@ -1125,6 +1125,7 @@ if test
>>>>> "${enable_pkcs11}" = "yes"; then ) fi
>>>>
>>>>> +CFLAGS="${CFLAGS} -std=c99" if test "${enable_pedantic}" =
>>>>> "yes"; then enable_strict="yes" CFLAGS="${CFLAGS}
>>>>> -pedantic"
>>>>
>>>>
>>>> I so much wants to give this an ACK. But this breaks CentOS
>>>> 5 builds very badly. The glibc-headers isn't prepared for
>>>> C99 on that distro.
>>>>
>>>> I took the latest git master where I could do a successful
>>>> build. Then I applied just this patch, and here is the
>>>> explosion: <http://paste.fedoraproject.org/417049/14725031/>
>>>>
>>>> To move towards C99, we need to add some tricks which makes
>>>> this not requiring users to overwrite C99 with C89. That
>>>> should happen automatically.
>>>>
>>>> Some CentOS 5.11 details: glibc-2.5-123.el5_11.3
>>>> glibc-headers-2.5-123.el5_11.3 gcc-4.1.2-55.el5
>>>> openssl-0.9.8e-40.el5_11 lzo-2.02-2.el5.1
>>>
>>> Did a bit more testing.
>>>
>>> -std=gnu89, -std=gnu99 Works very fine (compiles without
>>> errors).
>>>
>>> -std=c99 Makes glibc-headers explode, as already described
>>>
>>> -std=c89 Makes the LZ4 library we're shipping explode.
>
>> Hm, that's too bad. But I think we should still go for c99,
>> rather than gnu99. That should actually result in *more*
>> portable code on our side. The CentOS package maintainer can
>> then easily patch configure.ac (or configure) to use gnu99 for
>> arcane platforms.
>
> For the stock CentOS 5 package, it probably won't matter. That's
> indirectly maintained by Red Hat doing all kind of backports
> whenever needed.
>
> For the Fedora EPEL releases (which keeps our release cycles
> fairly tight), I'm adding Jon to this discussion directly as the
> main Fedora package maintainer for OpenVPN.
>
> Any thoughts on this, Jon?
Just some more benchmarks. I just compiled successfully with -std=c99
on an old Scientific Linux 6.5 (RHEL 6.5 clone) I found. Another
important detail, RHEL5 will reach the "End of Production" phase March
2017, OpenVPN have generally stopped supporting the oldest RHEL
releases once it hits EOL. RHEL 5 subscribers may purchase an
extended life cycle, but we have not cared too much about that so far.
There is one detail though regarding the patch itself. Your patch
adds -std=c99 to the CFLAGS quite early. The compile line gets quite
interesting if you try to swap this setting by using the recommended
approach:
./configure CFLAGS="$CFLAGS -std=gnu89"
Doing this results in the command line being run during compilation to
be be: gcc -std=gnu89 .... -std=c99 ...
So the -std argument appears twice. This should probably be avoided.
- --
kind regards,
David Sommerseth
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