Re: [Openvpn-devel] [PATCH (master)] Drop gnu89/c89 support, switch to c99

[David S. <op...@sf...>]

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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 <st...@ka...> ---
>> 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.


- -- 
kind regards,

David Sommerseth
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