I faced a similar problem a long time ago, I solved it by resetting the linker cache. Try this. # rm /etc/ld.so.cache # ldconfig On 5/12/19 6:20 PM, Stéphane Veyret wrote: > Le dim. 12 mai 2019 à 10:56, Florian Westphal <fw@xxxxxxxxx> a écrit : >> >>> Now, I am trying to modify the nftables userspace tool. I had to set variables: >>> LIBNFTNL_CFLAGS="-g -O2" >>> LIBNFTNL_LIBS=$HOME/libnftnl/src/.libs/libnftnl.so ./configure >>> in order for configure to work, but it worked. But at linking time, I >>> get the following error for each nftnl_* function: >>> ld: ./.libs/libnftables.so: undefined reference to `nftnl_trace_free' >>> >>> I tried to set the LD_LIBRARY_PATH to /usr/local/lib but it did not >>> change anything. Do you have an idea of what the problem is? >> >> Try >> >> LIBNFTNL_LIBS="-L$HOME/libnftnl/src/.libs -lnftnl" ./configure > > No luck, same result… :-( >