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Back in the 8.3 era we discovered that it was problematic if libpq.so had encoding ID assignments different from the backend, which is possible because on some platforms libpq.so might be of a different major version from the calling programs. psql should use libpq's assignments, but initdb has to use the backend's, else it will put wrong values into pg_database. The solution devised in commit8468146b0relied on giving initdb its own copy of encnames.c rather than relying on the functions exported by libpq. Later, that metamorphosed into ensuring that libpgcommon got linked before libpq -- which made things OK for initdb but broke psql. We didn't notice for lack of any changes in enum pg_enc since then. Commit06843df4areversed that, fixing the latent bug in psql but adding one in initdb. The meson build infrastructure is also not being sufficiently careful about link order, and trying to make it so would be equally fragile. Hence, let's use a new scheme based on giving the libpq-exported symbols different real names than the same functions exported from libpgcommon.a or libpgcommon_srv.a. (We could distinguish those two cases as well, but there seems no need to.) libpq gets the official names to avoid an ABI break for libpq clients, while the other cases use #define's to make the real names "xxx_private" rather than "xxx". By controlling where the #define's are applied, we can force any particular client program to use one set or the other of the encnames.c functions. We cannot back-patch this, since it'd be an ABI break for backend loadable modules, but there seems little need to. We're just trying to ensure that the world is safe for hypothetical future additions to enum pg_enc. In passing this should fix "duplicate symbol" linker warnings that we've been seeing on AIX buildfarm members since commit06843df4a. It's not very clear why that linker is complaining now, when there were strictly *more* duplicates visible before, but in any case this should remove the reason for complaint. Patch by me; thanks to Andres Freund for review. Discussion: https://postgr.es/m/2385119.1696354473@sss.pgh.pa.us
PostgreSQL Database Management System ===================================== This directory contains the source code distribution of the PostgreSQL database management system. PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings. PostgreSQL has many language interfaces, many of which are listed here: https://www.postgresql.org/download/ See the file INSTALL for instructions on how to build and install PostgreSQL. That file also lists supported operating systems and hardware platforms and contains information regarding any other software packages that are required to build or run the PostgreSQL system. Copyright and license information can be found in the file COPYRIGHT. A comprehensive documentation set is included in this distribution; it can be read as described in the installation instructions. The latest version of this software may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.