Does the link sequence of libthrift.a and libthriftnb.a matters?

[zd.wbh]

hi, all
     
   We encounter an odd link error today:

./src/transport/TBufferTransports.h:452: undefined reference to `vtable for 
apache::thrift::transport::TMemoryBuffer'
/usr/local/thrift/lib/libthriftnb.a(libthriftnb_la-TNonblockingServer.o)(.text+0x253e):
 In function `apache::thrift::server::TConnection::transition()':

  Normally, the "undefined reference of vtable" error arise from not 
implementing pure virtual functions, but not in our case. Finally we tried to 
exchange the link order of the two lib and get resolved. libthriftnb.a must be 
ahead of libthrift.a? Can somebody explains this to me? Thanks a lot.