pgsql: Fix "inconsistent DLL linkage" warning on Windows MSVC - Mailing list pgsql-committers

From Peter Eisentraut
Subject pgsql: Fix "inconsistent DLL linkage" warning on Windows MSVC
Date
Msg-id E1vHIru-005QgH-0j@gemulon.postgresql.org
Whole thread Raw
List pgsql-committers
Fix "inconsistent DLL linkage" warning on Windows MSVC

This warning was disabled in meson.build (warning 4273).  If you
enable it, it looks like this:

../src/backend/utils/misc/ps_status.c(27): warning C4273: '__p__environ': inconsistent dll linkage
C:\Program Files (x86)\Windows Kits\10\include\10.0.22621.0\ucrt\stdlib.h(1158): note: see previous definition of
'__p__environ'

The declaration in ps_status.c was:

    #if !defined(WIN32) || defined(_MSC_VER)
    extern char **environ;
    #endif

The declaration in the OS header file is:

    _DCRTIMP char***    __cdecl __p__environ (void);
    #define _environ  (*__p__environ())

So it is evident that this could be problematic.

The old declaration was required by the old MSVCRT library, but we
don't support that anymore with MSVC.

To fix, disable the re-declaration in ps_status.c, and also in some
other places that use the same code pattern but didn't trigger the
warning.

Then we can also re-enable the warning (delete the disablement in
meson.build).

Reviewed-by: Bryan Green <dbryan.green@gmail.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://www.postgresql.org/message-id/flat/bf060644-47ff-441b-97cf-c685d0827757@eisentraut.org

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/a3ea5330fcf47390c8ab420bbf433a97a54505d6

Modified Files
--------------
meson.build                         | 1 -
src/backend/postmaster/postmaster.c | 2 +-
src/backend/utils/misc/ps_status.c  | 2 +-
src/test/regress/regress.c          | 2 +-
4 files changed, 3 insertions(+), 4 deletions(-)


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