title: undefined reference while linking
body: <p>i have added a module to ns2 and i am compiling it when i get undefined reference error. </p>
  
  <pre><code>g++ -o ns \
  -lXext -lX11 -lnsl -ldl -lm -lm -lrt -lneoclassic -lxml
  maser/mamas.o: In function `mamasReasoner::mamasReasoner()':
  mamas.cc:(.text+0x95): undefined reference to `NeoEnvironment::initFromNs(std::basic_ostringstream&lt;char, std::char_traits&lt;char&gt;, std::allocator&lt;char&gt; &gt;&amp;, std::basic_ostringstream&lt;char, std::char_traits&lt;char&gt;, std::allocator&lt;char&gt; &gt;&amp;, int)'
  maser/mamas.o: In function `mamasReasoner::build_ontology_tree(knBase&amp;)':
  mamas.cc:(.text+0x1c84): undefined reference to `NeoEnvironment::evaluateCommand(String const&amp;)'
  maser/mamas.o: In function `NeoEnvironment::readXmlFromMemory(char const*, char const*)':
  mamas.cc:(.text._ZN14NeoEnvironment17readXmlFromMemoryEPKcS1_[NeoEnvironment::readXmlFromMemory(char const*, char const*)]+0x14): undefined reference to `Parser::readXmlFromMemory(char const*, char const*)'
  collect2: ld returned 1 exit status
  make: *** [ns] Error
  </code></pre>
  
  <p>the library which it is asking for is present at the <code>/usr/local/lib/libneoclassic.so</code> and the makefile can be seen here <a href="http://pastebin.com/NZWPxKht" rel="nofollow">http://pastebin.com/NZWPxKht</a>
  which use the following code for linking.</p>
  
  <pre><code>LINK    = g++
  LDFLAGS =  -lneoclassic -lrt -lxml2
  LDOUT   = -o $(BLANK)
  LIB     = \
          -L/usr/local/lib -ltclcl -L/usr/local/lib -lotcl -L/usr/local/lib -ltk8.4 -L/usr/local/lib -ltcl8.4 \
          -lXext -lX11 \
           -lnsl -ldl \
          -lm -lm
  OBJ_CC = \
          tools/random.o tools/rng.o tools/ranvar.o common/misc.o common/timer-handler.o \
          common/scheduler.o common/object.o common/packet.o \
          common/ip.o routing/route.o common/connector.o common/ttl.o \
          trace/trace.o trace/trace-ip.o \
          classifier/classifier.o classifier/classifier-addr.o \
          classifier/classifier-hash.o \
          classifier/classifier-virtual.o \
          classifier/classifier-mcast.o \
          classifier/classifier-bst.o \
          classifier/classifier-mpath.o mcast/replicator.o \
          classifier/classifier-mac.o \
          classifier/classifier-qs.o \
          classifier/classifier-port.o src_rtg/classifier-sr.o \
          src_rtg/sragent.o src_rtg/hdr_src.o adc/ump.o \
          qs/qsagent.o qs/hdr_qs.o \
          apps/app.o apps/telnet.o tcp/tcplib-telnet.o \
          tools/trafgen.o trace/traffictrace.o tools/pareto.o \
          tools/expoo.o tools/cbr_traffic.o \
          adc/tbf.o adc/resv.o adc/sa.o tcp/saack.o \
          tools/measuremod.o adc/estimator.o adc/adc.o adc/ms-adc.o \
          adc/timewindow-est.o adc/acto-adc.o \
          adc/pointsample-est.o adc/salink.o adc/actp-adc.o \
          adc/hb-adc.o adc/expavg-est.o\
          adc/param-adc.o adc/null-estimator.o \
          adc/adaptive-receiver.o apps/vatrcvr.o adc/consrcvr.o \
          common/agent.o common/message.o apps/udp.o \
          common/session-rtp.o apps/rtp.o tcp/rtcp.o \
          common/ivs.o \
          common/messpass.o common/tp.o common/tpm.o apps/worm.o \
          tcp/tcp.o tcp/tcp-sink.o tcp/tcp-reno.o \
          tcp/tcp-newreno.o \
          tcp/tcp-vegas.o tcp/tcp-rbp.o tcp/tcp-full.o tcp/rq.o \
          baytcp/tcp-full-bay.o baytcp/ftpc.o baytcp/ftps.o \
          tcp/scoreboard.o tcp/scoreboard-rq.o tcp/tcp-sack1.o tcp/tcp-fack.o \
          tcp/tcp-asym.o tcp/tcp-asym-sink.o tcp/tcp-fs.o \
          tcp/tcp-asym-fs.o \
          tcp/tcp-int.o tcp/chost.o tcp/tcp-session.o \
          tcp/nilist.o \
          sctp/sctp.o apps/sctp_app1.o\
          sctp/sctp-timestamp.o sctp/sctp-hbAfterRto.o \
          sctp/sctp-multipleFastRtx.o sctp/sctp-mfrHbAfterRto.o \
          sctp/sctp-mfrTimestamp.o \
          sctp/sctp-cmt.o \
          sctp/sctpDebug.o \
          tools/integrator.o tools/queue-monitor.o \
          tools/flowmon.o tools/loss-monitor.o \
          queue/queue.o queue/drop-tail.o \
          adc/simple-intserv-sched.o queue/red.o \
          queue/semantic-packetqueue.o queue/semantic-red.o \
          tcp/ack-recons.o \
          queue/sfq.o queue/fq.o queue/drr.o queue/srr.o queue/cbq.o \
          queue/jobs.o queue/marker.o queue/demarker.o \
          link/hackloss.o queue/errmodel.o queue/fec.o\
          link/delay.o tcp/snoop.o \
          gaf/gaf.o \
          link/dynalink.o routing/rtProtoDV.o common/net-interface.o \
          mcast/ctrMcast.o mcast/mcast_ctrl.o mcast/srm.o \
          common/sessionhelper.o queue/delaymodel.o \
          mcast/srm-ssm.o mcast/srm-topo.o \
          routing/alloc-address.o routing/address.o \
          $(LIB_DIR)int.Vec.o $(LIB_DIR)int.RVec.o \
          $(LIB_DIR)dmalloc_support.o \
          webcache/http.o webcache/tcp-simple.o webcache/pagepool.o \
          webcache/inval-agent.o webcache/tcpapp.o webcache/http-aux.o \
          webcache/mcache.o webcache/webtraf.o \
          webcache/webserver.o \
          webcache/logweb.o \
          empweb/empweb.o \
          empweb/empftp.o \
          realaudio/realaudio.o \
          mac/lanRouter.o classifier/filter.o \
          common/pkt-counter.o \
          common/Decapsulator.o common/Encapsulator.o \
          common/encap.o \
          mac/channel.o mac/mac.o mac/ll.o mac/mac-802_11.o \
          mac/mac-802_3.o mac/mac-tdma.o mac/smac.o \
          mobile/mip.o mobile/mip-reg.o mobile/gridkeeper.o \
          mobile/propagation.o mobile/tworayground.o \
          mobile/antenna.o mobile/omni-antenna.o \
          mobile/shadowing.o mobile/shadowing-vis.o mobile/dumb-agent.o \
          common/bi-connector.o common/node.o \
          common/mobilenode.o \
          mac/arp.o mobile/god.o mobile/dem.o \
          mobile/topography.o mobile/modulation.o \
          queue/priqueue.o queue/dsr-priqueue.o \
          mac/phy.o mac/wired-phy.o mac/wireless-phy.o \
          mac/mac-timers.o trace/cmu-trace.o mac/varp.o \
          mac/mac-simple.o \
          satellite/sat-hdlc.o \
          dsdv/dsdv.o dsdv/rtable.o queue/rtqueue.o \
          routing/rttable.o \
          imep/imep.o imep/dest_queue.o imep/imep_api.o \
          imep/imep_rt.o imep/rxmit_queue.o imep/imep_timers.o \
          imep/imep_util.o imep/imep_io.o \
          tora/tora.o tora/tora_api.o tora/tora_dest.o \
          tora/tora_io.o tora/tora_logs.o tora/tora_neighbor.o \
          dsr/dsragent.o dsr/hdr_sr.o dsr/mobicache.o dsr/path.o \
          dsr/requesttable.o dsr/routecache.o dsr/add_sr.o \
          dsr/dsr_proto.o dsr/flowstruct.o dsr/linkcache.o \
          dsr/simplecache.o dsr/sr_forwarder.o \
          aodv/aodv_logs.o aodv/aodv.o \
          aodv/aodv_rtable.o aodv/aodv_rqueue.o \
          common/ns-process.o \
          satellite/satgeometry.o satellite/sathandoff.o \
          satellite/satlink.o satellite/satnode.o \
          satellite/satposition.o satellite/satroute.o \
          satellite/sattrace.o \
          rap/raplist.o rap/rap.o rap/media-app.o rap/utilities.o \
          common/fsm.o tcp/tcp-abs.o \
          diffusion/diffusion.o diffusion/diff_rate.o diffusion/diff_prob.o \
          diffusion/diff_sink.o diffusion/flooding.o diffusion/omni_mcast.o \
          diffusion/hash_table.o diffusion/routing_table.o diffusion/iflist.o \
          tcp/tfrc.o tcp/tfrc-sink.o mobile/energy-model.o apps/ping.o tcp/tcp-rfc793edu.o \
          queue/rio.o queue/semantic-rio.o tcp/tcp-sack-rh.o tcp/scoreboard-rh.o \
          plm/loss-monitor-plm.o plm/cbr-traffic-PP.o \
          linkstate/hdr-ls.o \
          mpls/classifier-addr-mpls.o mpls/ldp.o mpls/mpls-module.o \
          routing/rtmodule.o classifier/classifier-hier.o \
          routing/addr-params.o \
           nix/hdr_nv.o nix/classifier-nix.o \
           nix/nixnode.o \
           routealgo/rnode.o \
           routealgo/bfs.o \
           routealgo/rbitmap.o \
           routealgo/rlookup.o \
           routealgo/routealgo.o \
           nix/nixvec.o \
          nix/nixroute.o \
          diffserv/dsred.o diffserv/dsredq.o \
          diffserv/dsEdge.o diffserv/dsCore.o \
          diffserv/dsPolicy.o diffserv/ew.o diffserv/dewp.o \
          queue/red-pd.o queue/pi.o queue/vq.o queue/rem.o \
          queue/gk.o \
          pushback/rate-limit.o pushback/rate-limit-strategy.o \
          pushback/ident-tree.o pushback/agg-spec.o \
          pushback/logging-data-struct.o \
          pushback/rate-estimator.o \
          pushback/pushback-queue.o pushback/pushback.o \
          common/parentnode.o trace/basetrace.o \
          common/simulator.o asim/asim.o \
          common/scheduler-map.o common/splay-scheduler.o \
          linkstate/ls.o linkstate/rtProtoLS.o \
          pgm/classifier-pgm.o pgm/pgm-agent.o pgm/pgm-sender.o \
          pgm/pgm-receiver.o mcast/rcvbuf.o \
          mcast/classifier-lms.o mcast/lms-agent.o mcast/lms-receiver.o \
          mcast/lms-sender.o \
          queue/delayer.o \
          xcp/xcpq.o xcp/xcp.o xcp/xcp-end-sys.o \
          wpan/p802_15_4csmaca.o wpan/p802_15_4fail.o \
          wpan/p802_15_4hlist.o wpan/p802_15_4mac.o \
          wpan/p802_15_4nam.o wpan/p802_15_4phy.o \
          wpan/p802_15_4sscs.o wpan/p802_15_4timer.o \
          wpan/p802_15_4trace.o wpan/p802_15_4transac.o \
          maser/maser.o maser/mamas.o \
          $(OBJ_STL)
  
  $(LINK) $(LDFLAGS) $(LDOUT)$@ \
                      common/tclAppInit.o $(OBJ) $(LIB)
  </code></pre>