On Wed, 2020-11-18 at 14:46 +0100, Eric Svenson wrote: > I am not really sure if I am in the right mailing list, but I try it here first. > > I have written a postgres C extension as DLL which was used with Postgres 9.2 successfully. > > Now I am trying to upgrade to Postgres 13 but I ran into a compile problem. > > The function > > PG_GETARG_BYTEA_P > > causes the compile error > > error LNK2019: unresolved external symbol _pg_detoast_datum referenced in function _compressBytea > > The Compiler is > Microsoft Visual Studio 2010 > Windows 10 > > Any idea what to do? Is PG_GETARG_BYTEA_P obsolete? In PostgreSQL v13, "PG_GETARG_BYTEA_P(n)" is a macro that resolves to "((bytea *) pg_detoast_datum((struct varlena *) DatumGetPointer(fcinfo->args[n].value)))". This has not changed since 9.2, as far as I can tell. The underscore in front of the function name is relevant: perhaps you compile your function using a different "calling convention" than was used to build PostgreSQL? Sorry, but I am not a Windows expert. Yours, Laurenz Albe -- Cybertec | https://www.cybertec-postgresql.com