Re: Make copyObject work in C++ - Mailing list pgsql-hackers

From Bryan Green
Subject Re: Make copyObject work in C++
Date
Msg-id b03ddcd4-2a16-49ee-b105-e7f609f3c514@gmail.com
Whole thread Raw
In response to Re: Make copyObject work in C++  ("Jelte Fennema-Nio" <postgres@jeltef.nl>)
List pgsql-hackers
On 1/25/2026 6:42 AM, Jelte Fennema-Nio wrote:
> On Tue Jan 20, 2026 at 5:28 PM CET, Peter Eisentraut wrote:
>> I have split your first patch further.  For a start, I left out the
>> PG_MODULE_MAGIC*-related changes and disabled the module under MSVC.
>> This has been committed.  I plan to let the buildfarm run with it for
>> a day or two and then add in the basic MSVC support.
> 
> To hopefully make your life a bit easier. Here's a rebased version that
> enables the MSVC support again, with an updated commit message.
> 
This causes the build to break on VS 2022.  Versions prior do not have
support for __typeof_unqual__.  This would have led to
HAVE_TYPEOF_UNQUAL being not defined on the buildfarm causing the
fallback to copyObjectImpl() for VS 2019.

When you build on VS 2022 you will get an error:
../src/backend/commands/event_trigger.c(1901): error C2100: you cannot
dereference an operand of type 'void'

VS 2022 (MSVC) does not handle the void * dereference the way gcc/clang
does (thanks to GNU extensions, I believe).  It exposes
__typeof_unqual__ even it C11, but enforces strict C semantics on the
void * dereference.  To work on this platform the call
copyObject(lfirst(cell)) would need to have a cast to the correct
concrete type: copyObject((Node *)lfirst(cell)).

I was about to update to VS 2026, but now I think I should have an
instance of VS from 2019, 2022, and 2026.

-- 
Bryan Green
EDB: https://www.enterprisedb.com



pgsql-hackers by date:

Previous
From: Fujii Masao
Date:
Subject: Re: Allow GUC settings in CREATE SUBSCRIPTION CONNECTION to take effect
Next
From: Zsolt Parragi
Date:
Subject: Re: Flush some statistics within running transactions