On Wed, Feb 08, 2006 at 06:57:11PM -0400, Rodolfo Campos wrote: > When I tried to connect using libpq I got errors too. But this time the > error is trying to register the function in postgresql, the RDBMS tells me > that the function PQconnectdb is undefined. > > I don't obtain errors compiling the code. The command that I used was: > > gcc -fpic -shared -I/usr/include/postgresql -I/usr/include/postgresql/server > -lpq test.c -o test.so
What does "ldd ./test.so" show? You might need to specify additional flags to give hints about libpq's location to the runtime linker; another possibility would be to set an environment variable like LD_LIBRARY_PATH.
Have a look at contrib/dblink/Makefile and "Extension Building Infrastructure" in the documentation (8.0 and later). It's usually easiest to let PostgreSQL figure out how to build extensions.