Re: Windows vs C99 (was Re: C99 compliance for src/port/snprintf.c)

On Tue, Aug 21, 2018 at 11:16 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Andres Freund <andres(at)anarazel(dot)de> writes:
>> On 2018-08-21 13:29:20 -0400, Tom Lane wrote:
>>> We've got a buildfarm handy that could answer the question.
>>> Let's just stick a test function in there for a day and see
>>> which animals fail.
>
>> I think we pretty much know the answer already, anything before 2013
>> will fail.
>
> Do we know that for sure? I thought it was theoretical.
>

I have MSVC 2010 on my Windows 7 VM where I have tried the C99
constructs provided by Peter E. and below are my findings:

Tried compiling below function in one of the .c files in the src/backend
-----------------------------------------------------------------------------------------------
int
bar()
{
int x;
x = 1;
int y;
y = 2;

for (int i = 0; i < 5; i++)
;

return 0;
}

error C2143: syntax error : missing ';' before 'type'
error C2065: 'y' : undeclared identifier
error C2143: syntax error : missing ';' before 'type'
error C2143: syntax error : missing ';' before 'type'
error C2143: syntax error : missing ')' before 'type'
error C2143: syntax error : missing ';' before 'type'
error C2065: 'i' : undeclared identifier
warning C4552: '<' : operator has no effect; expected operator with side-effect
error C2065: 'i' : undeclared identifier
error C2059: syntax error : ')'

Tried compiling below struct in one of the .c files in the src/backend
-----------------------------------------------------------------------------------------------
struct foo
{
int a;
int b;
};

struct foo f = {
.a = 1,
.b = 2
};

error C2059: syntax error : '.'

I have also tried compiling above in standalone console application
project in MSVC 2010 and able to compile the function successfully,
but struct is giving the same error as above. So, it seems to me that
it won't work on <= MSVC 2010. I am personally okay with upgrading my
Windows VM.

I have found a couple of links which suggest that MSVC 2015 has a good
amount of conformance with C99 [1]. It seems MSVC 2013 also has
decent support for C99 [2], but I am not able to verify if the
constructs shared by Peter E can be compiled on it.

[1] https://social.msdn.microsoft.com/Forums/en-US/fa17bcdd-7165-4645-a676-ef3797b95918/details-on-c99-support-in-msvc?forum=vcgeneral
[2] https://blogs.msdn.microsoft.com/vcblog/2013/07/19/c99-library-support-in-visual-studio-2013/

--
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com