Hi Tom, Thanks for the tip, I altered the gcc invocation as follows: Here are the two gcc invocations originally creating the shared library: gcc -Wall -fPIC -c mylibrary.c -o mylibrary.o \ -I $(A) -I $(B) -I $(C) -I $(E) -lhdfs gcc -I $(A) -I $(B) -I $(C) -I $(E) -shared\ -Wl,-soname,mylibrary.so -o mylibrary.so mylibrary.o ############################# Here's the new invocations: I added "-lhdfs" to the second gcc invocation. gcc -I $(A) -I $(B) -I $(C) -I $(E) -shared\ -lhdfs -Wl,-soname,mylibrary.so -o mylibrary.so mylibrary.o Now I can see the libraries! ldd mylibrary.so linux-vdso.so.1 => (0x00007fff499c5000) libhdfs.so.0 => /usr/lib/libhdfs.so.0 (0x00007f44e4739000) libc.so.6 => /lib/libc.so.6 (0x00007f44e43b6000) libjvm.so => /usr/lib/jvm/java-6- openjdk/jre/lib/amd64/server/libjvm.so (0x00007f44e3866000) libdl.so.2 => /lib/libdl.so.2 (0x00007f44e3662000) libpthread.so.0 => /lib/libpthread.so.0 (0x00007f44e3445000) /lib64/ld-linux-x86-64.so.2 (0x00007f44e4b66000) libm.so.6 => /lib/libm.so.6 (0x00007f44e31c1000) > "Rob_pg" <robert7390@xxxxxxxxxxx> writes: > > I've been working on creating a foreign data wrapper for hdfs on using > > version 9.1.0. This is my first time creating C functions against > > postgres, so hopefully this falls under the 'newbie' category and is > > easy to solve. > > > > The source code code does compile resulting in a shared library: > > > > file mylibrary.so: ELF 64-bit LSB shared object, x86-64, version 1 > > (SYSV), dynamically linked, not stripped > > > > ldd mylibrary.so > > > > linux-vdso.so.1 => (0x00007fff40fff000) > > libc.so.6 => /lib/libc.so.6 (0x00007f3adb8cc000) > > /lib64/ld-linux-x86-64.so.2 (0x00007f3adbe72000) > > The reason it's not working is that libhdfs.so isn't listed as a > requirement for mylibrary.so. You did not show us your link command > for mylibrary.so, but most likely there needs to be a -lhdfs in it. > > regards, tom lane -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general