linux 链接动态库时产生如下错误

g++ ADS_APIServer.o ../../udt/src/libudt.so ../Commlib/libCommlib.so libADS_APIServer.so -o ADS_APIServer
ADS_APIServer.o: In function soapOpenThread(void*)':
ADS_APIServer.cpp:(.text+0x8b0): undefined reference topthread_create'
ADS_APIServer.o: In function main':
ADS_APIServer.cpp:(.text+0xd85): undefined reference topthread_create'
ADS_APIServer.cpp:(.text+0xdb1): undefined reference to pthread_create'
ADS_APIServer.cpp:(.text+0xddd): undefined reference topthread_create'
ADS_APIServer.cpp:(.text+0xe09): undefined reference to pthread_create'
ADS_APIServer.o:ADS_APIServer.cpp:(.text+0xe38): more undefined references topthread_create' follow
../../udt/src/libudt.so: undefined reference to pthread_mutex_trylock'
../Commlib/libCommlib.so: undefined reference topthread_mutexattr_settype'
../../udt/src/libudt.so: undefined reference to pthread_key_create'
../Commlib/libCommlib.so: undefined reference todlsym'
../Commlib/libCommlib.so: undefined reference to dlerror'
../../udt/src/libudt.so: undefined reference topthread_getspecific'
../Commlib/libCommlib.so: undefined reference to pthread_mutexattr_destroy'
../Commlib/libCommlib.so: undefined reference topthread_mutexattr_init'
../../udt/src/libudt.so: undefined reference to pthread_key_delete'
../Commlib/libCommlib.so: undefined reference todlopen'
../../udt/src/libudt.so: undefined reference to pthread_setspecific'
../Commlib/libCommlib.so: undefined reference todlclose'
../../udt/src/libudt.so: undefined reference to `pthread_join'