Re: Linker errors while creating a PostgreSQL C extension function.

TalGloz wrote:
> Do you or anyone know why is it trying to link with -L/usr/lib64 path and
> not -L/usr/local/lib as provided?
> 
> After recompiling the libseal.a with the -fPIC flag and copying it manually
> from /usr/local/lib/ to /usr/lib64/ I get those errors:
> 
> g++ -Wl,--no-undefined -shared -o seal_diff_cpp.so seal_diff_cpp.o
> -L/usr/pgsql-10/lib   -L/usr/lib64 -Wl,--as-needed
> -Wl,-rpath,'/usr/pgsql-10/lib',--enable-new-dtags -L/usr/local/lib -lseal
> -pthread
> seal_diff_cpp.o: In function `seal_diff_cpp':
> /etc/opt/pgsql_c_functions/CPP/seal_extension/seal_diff_cpp.cpp:106:
> undefined reference to `pg_detoast_datum_packed'
> /etc/opt/pgsql_c_functions/CPP/seal_extension/seal_diff_cpp.cpp:107:
> undefined reference to `pg_detoast_datum_packed'
> /etc/opt/pgsql_c_functions/CPP/seal_extension/seal_diff_cpp.cpp:108:
> undefined reference to `pg_detoast_datum_packed'
> /etc/opt/pgsql_c_functions/CPP/seal_extension/seal_diff_cpp.cpp:112:
> undefined reference to `text_to_cstring'
> /etc/opt/pgsql_c_functions/CPP/seal_extension/seal_diff_cpp.cpp:113:
> undefined reference to `text_to_cstring'
> /etc/opt/pgsql_c_functions/CPP/seal_extension/seal_diff_cpp.cpp:114:
> undefined reference to `text_to_cstring'
> /etc/opt/pgsql_c_functions/CPP/seal_extension/seal_diff_cpp.cpp:130:
> undefined reference to `cstring_to_text_with_len'
> 
> Did I miss something in one of my files?

I think the --no-undefined is wrong.

Any reference to PostgreSQL functions is undefined at build time and
gets resolved when the shared library is loaded into PostgreSQL.

Yours,
Laurenz Albe
-- 
Cybertec | https://www.cybertec-postgresql.com