Re: Make copyObject work in C++

Peter Eisentraut <peter@eisentraut.org>

From: Peter Eisentraut <peter@eisentraut.org>

To: Jelte Fennema-Nio <postgres@jeltef.nl>

Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Thomas Munro <thomas.munro@gmail.com>, Andres Freund <andres@anarazel.de>

Date: 2026-03-31T08:33:36Z

Lists: pgsql-hackers

Attachments

0001-Enable-test_cplusplusext-with-MSVC.patch (text/plain) patch 0001

On 30.03.26 00:53, Jelte Fennema-Nio wrote:
> On Fri, 27 Mar 2026 at 12:23, Peter Eisentraut <peter@eisentraut.org> 
> wrote:
>> Here is another tidied up patch set for this.  I didn't go quite as far
>> as enabling C++20 by default in meson.build, this would just take more
>> time to work out and test all the different combinations, but I added
>> the flag to the Cirrus CI task, since there we know what compiler we 
>> have.
> 
> I think 0001 and 0002 are good.
> 
> 0003 seems awkward though. Attached is an approach that I think is
> better: It actually checks for the required featureset and adds the
> necessary flags to the compiler.

Hmm, note that C++ is also used for LLVM/JIT, and by requiring this 
additional feature set we are also imposing new requirements for those 
users.  This has not been fully explored, and I hesitate to add such a 
new requirement at the last moment.

But how about this: We add the feature test that you propose and enable 
the extension based on that.  See attached patch.  This reduces to 
essentially a three-line patch, much simpler than all previous proposals.

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

Enable test_cplusplusext with MSVC
- c05ad248f99c 19 (unreleased) landed
Disable some C++ warnings in MSVC
- 82a7cbea747c 19 (unreleased) landed
meson: Make room for C++-only warning flags for MSVC
- 4c83f1253593 19 (unreleased) landed
Make fixed-length list building macros work in C++
- f8e7ca328510 19 (unreleased) landed
Make unconstify and unvolatize use StaticAssertVariableIsOfTypeMacro
- 258248d0bdbf 19 (unreleased) landed
Use typeof everywhere instead of compiler specific spellings
- e2308350c9b7 19 (unreleased) landed
Test List macros in C++ extensions
- 3d28ecb5ac76 19 (unreleased) landed
Test most StaticAssert macros in C++ extensions
- 451650eaacd5 19 (unreleased) landed
Revert "Change copyObject() to use typeof_unqual"
- 0af05b5dbb42 19 (unreleased) landed
Fix for C++ compatibility
- b4555cb070f1 19 (unreleased) landed
tests: Add a test C++ extension module
- 476b35d4e311 19 (unreleased) landed