Re: alignas (C11)

Peter Eisentraut <peter@eisentraut.org>

From: Peter Eisentraut <peter@eisentraut.org>

To: pgsql-hackers <pgsql-hackers@postgresql.org>

Date: 2025-12-01T07:03:49Z

Lists: pgsql-hackers

On 12.11.25 12:39, Peter Eisentraut wrote:
> Here, I'm proposing to make some use of the alignas specifier.  This 
> takes the place of compiler extensions such as 
> __attribute__((aligned(a))) and __declspec(align(a)), packaged up as 
> pg_attribute_aligned(a), which are used in a variety of places.  Also, 
> we can simplify some places where unions are used to encourage 
> alignment, and remove a few workaround for lack of alignment attribute 
> support.

This patch set has been committed, it looks like without buildfarm 
complaints.

Commits

Further fix extended alignment for older g++.
- bd9dfac8b121 19 (unreleased) landed
Disable extended alignment uses on older g++
- 6ceef9408c26 19 (unreleased) landed
Work around buggy alignas in older g++
- a9bdb63bba8a 19 (unreleased) landed
Use C11 alignas in pg_atomic_uint64 definitions
- e7075a3405cc 19 (unreleased) landed
C11 alignas instead of unions -- extended alignments
- d4c0f91f7d57 19 (unreleased) landed
C11 alignas instead of unions
- 97e04c74bedb 19 (unreleased) landed
Add <stdalign.h> to c.h
- 300c8f532478 19 (unreleased) landed