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From: Peter Eisentraut <[email protected]>
To: [email protected]
Subject: pgsql: Support using copyObject in standard C++
Date: Mon, 02 Mar 2026 10:55:25 +0000
Message-ID: <[email protected]> (raw)

Support using copyObject in standard C++

Calling copyObject in C++ without GNU extensions (e.g. when using
-std=c++11 instead of -std=gnu++11) fails with an error like this:

error: use of undeclared identifier 'typeof'; did you mean 'typeid'

This is due to the C compiler used to compile PostgreSQL supporting
typeof, but that function actually not being present in the C++
compiler.  This fixes that by explicitely checking for typeof support
in C++, and then either use that or define typeof ourselves as:

    std::remove_reference_t<decltype(x)>

According to the paper that led to adding typeof to the C standard,
that's the C++ equivalent of the C typeof:
https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2927.htm#existing-decltype

Author: Author: Jelte Fennema-Nio <[email protected]>
Discussion: https://www.postgresql.org/message-id/flat/DGPW5WCFY7WY.1IHCDNIVVT300%2540jeltef.nl

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/1887d822f1428637c935b9f5e8be4a2a56fb77c7

Modified Files
--------------
config/c-compiler.m4                               | 29 ++++++++++++
configure                                          | 54 ++++++++++++++++++++++
configure.ac                                       |  1 +
meson.build                                        | 25 ++++++++++
src/include/c.h                                    | 21 +++++++++
src/include/pg_config.h.in                         |  7 +++
.../test_cplusplusext/test_cplusplusext.cpp        |  2 +
7 files changed, 139 insertions(+)



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