C++ CMake链接错误（collect2:ld返回1退出状态）

下面的项目结构是一个简化的示例

├── CMakeLists.txt
├── debug
├── CommBase
│   ├── Task.h
│   ├── Task.cpp
│   ├── Thread.h
│   ├── Thread.cpp
│   └── CMakeLists.txt
├── NetWork
│   ├── TSocket.h
│   ├── TSocket.cpp
│   ├── Stream_Channel.h
│   ├── Stream_Channel.cpp
│   └── CMakeLists.txt
├── MessageDispatch
│   ├── Channel_Manager.h
│   ├── Channel_Manager.cpp
│   ├── Message_Facade.h
│   ├── Message_Facade.cpp
│   └── CMakeLists.txt
└── DemoServer
    ├── CMakeLists.txt
    └── main.cpp

/CMakeLists.txt

CommBase/CMakeLists.txt

网络/CMakeLists.txt

MessageDispatch/CMakeLists.txt

DemoServer/CMakeLists.txt

链接CXX可执行文件服务器

/usr/bin/cmake -E cmake_link_script CMakeFiles/DemoServer.dir/link.txt --verbose=1
/usr/bin/c++     -fPIC CMakeFiles/DemoServer.dir/stdafx.cpp.o CMakeFiles/DemoServer.dir/DemoServer.cpp.o  -o DemoServer -rdynamic -lCommBase -lNetWork -lMessageDispatch 
/usr/local/lib/libMessageDispatch.a(Message_Facade.cpp.o): In function `Message_Facade::stop()':
/home/cl/server/ddsvn/MessageDispatch/Message_Facade.cpp:80: undefined reference to `Timer_Queue::instance()'
/home/cl/server/ddsvn/MessageDispatch/Message_Facade.cpp:80: undefined reference to `Timer_Queue::stop()'
/usr/local/lib/libMessageDispatch.a(Message_Facade.cpp.o): In function `Message_Facade::wait()':
/home/cl/server/ddsvn/MessageDispatch/Message_Facade.cpp:87: undefined reference to `Task::wait()'
/home/cl/server/ddsvn/MessageDispatch/Message_Facade.cpp:88: undefined reference to `Task::wait()'
/usr/local/lib/libMessageDispatch.a(Acceptor_Manager.cpp.o): In function `Stream_Acceptor':
/home/cl/server/ddsvn/MessageDispatch/../NetWork/Stream_Accecptor.h:40: undefined reference to `vtable for Stream_Acceptor'
/usr/local/lib/libMessageDispatch.a(Channel_Manager.cpp.o): In function `Channel_Manager':
/home/cl/server/ddsvn/MessageDispatch/Channel_Manager.cpp:81: undefined reference to `Channel_Handler::~Channel_Handler()'
/usr/local/lib/libMessageDispatch.a(Channel_Manager.cpp.o): In function `~Channel_Manager':
/home/cl/server/ddsvn/MessageDispatch/Channel_Manager.cpp:86: undefined reference to `Channel_Handler::~Channel_Handler()'
/home/cl/server/ddsvn/MessageDispatch/Channel_Manager.cpp:86: undefined reference to `Channel_Handler::~Channel_Handler()'
/usr/local/lib/libMessageDispatch.a(Channel_Manager.cpp.o): In function `Channel_Handler':
/home/cl/server/ddsvn/MessageDispatch/../NetWork/Channel_Handler.h:14: undefined reference to `vtable for Channel_Handler'
/usr/local/lib/libMessageDispatch.a(Channel_Manager.cpp.o):(.rodata._ZTI15Channel_Manager[typeinfo for Channel_Manager]+0x28): undefined reference to `typeinfo for Channel_Handler'
/usr/local/lib/libMessageDispatch.a(Message.cpp.o): In function `Message':
/home/cl/server/ddsvn/MessageDispatch/Message.cpp:49: undefined reference to `Binary_Stream::Binary_Stream(int)'
/home/cl/server/ddsvn/MessageDispatch/Message.cpp:98: undefined reference to `Binary_Stream::~Binary_Stream()'
/home/cl/server/ddsvn/MessageDispatch/Message.cpp:100: undefined reference to `Binary_Stream::Binary_Stream(int)'
/usr/local/lib/libMessageDispatch.a(Message.cpp.o): In function `Message::resize(int)':
/home/cl/server/ddsvn/MessageDispatch/Message.cpp:187: undefined reference to `Stream_Base::resize(int)'
/home/cl/server/ddsvn/MessageDispatch/Message.cpp:196: undefined reference to `Stream_Base::resize(int)'
/usr/local/lib/libMessageDispatch.a(Message.cpp.o): In function `~Message':
/home/cl/server/ddsvn/MessageDispatch/Message.cpp:203: undefined reference to `Binary_Stream::~Binary_Stream()'
/home/cl/server/ddsvn/MessageDispatch/Message.cpp:203: undefined reference to `Binary_Stream::~Binary_Stream()'
/usr/local/lib/libMessageDispatch.a(Message.cpp.o):(.rodata._ZTV7Message[vtable for Message]+0x20): undefined reference to `Stream_Base::clone_stream()'
/usr/local/lib/libMessageDispatch.a(Message.cpp.o):(.rodata._ZTI7Message[typeinfo for Message]+0x10): undefined reference to `typeinfo for Binary_Stream'
/usr/local/lib/libMessageDispatch.a(Connector_Manager.cpp.o): In function `Stream_Connector':
/home/cl/server/ddsvn/MessageDispatch/../NetWork/Stream_Connector.h:42: undefined reference to `vtable for Stream_Connector'
/usr/local/lib/libMessageDispatch.a(Context.cpp.o): In function `Context':
/home/cl/server/ddsvn/MessageDispatch/Context.cpp:15: undefined reference to `Dispatch_Thread::Dispatch_Thread()'
/usr/local/lib/libMessageDispatch.a(Context.cpp.o): In function `Context::initialize()':
/home/cl/server/ddsvn/MessageDispatch/Context.cpp:113: undefined reference to `Timer_Queue::instance()'
/home/cl/server/ddsvn/MessageDispatch/Context.cpp:113: undefined reference to `Timer_Queue::start()'
/home/cl/server/ddsvn/MessageDispatch/Context.cpp:116: undefined reference to `Task::activate(int, int*)'
/home/cl/server/ddsvn/MessageDispatch/Context.cpp:121: undefined reference to `Task::activate(int, int*)'
/usr/local/lib/libMessageDispatch.a(Re_Connect_Handler.cpp.o): In function `Re_Connect_Handler::process_re_connect(Context&, int)':
/home/cl/server/ddsvn/MessageDispatch/Re_Connect_Handler.cpp:23: undefined reference to `Timer_Queue::instance()'
/home/cl/server/ddsvn/MessageDispatch/Re_Connect_Handler.cpp:23: undefined reference to `Timer_Queue::schedule_timer(Smart_Ptr<Timer_Handler>, Time_Value const&, Smart_Ptr<Ref_Object>, EDispatchType, Dispatch_Thread*)'
/usr/local/lib/libMessageDispatch.a(IO_Thread.cpp.o): In function `IO_Thread':
/home/cl/server/ddsvn/MessageDispatch/IO_Thread.cpp:4: undefined reference to `Task::Task()'
/home/cl/server/ddsvn/MessageDispatch/IO_Thread.cpp:7: undefined reference to `Task::~Task()'
/usr/local/lib/libMessageDispatch.a(IO_Thread.cpp.o): In function `~IO_Thread':
/home/cl/server/ddsvn/MessageDispatch/IO_Thread.cpp:12: undefined reference to `Task::~Task()'
/home/cl/server/ddsvn/MessageDispatch/IO_Thread.cpp:12: undefined reference to `Task::~Task()'
/usr/local/lib/libMessageDispatch.a(IO_Thread.cpp.o):(.rodata._ZTI9IO_Thread[typeinfo for IO_Thread]+0x10): undefined reference to `typeinfo for Task'
collect2: ld returned 1 exit status
make[2]: *** [DemoServer] Error 1
make[2]: Leaving directory `/home/cl/server/ddsvn/DemoServer/Debug'
make[1]: *** [CMakeFiles/DemoServer.dir/all] Error 2
make[1]: Leaving directory `/home/cl/server/ddsvn/DemoServer/Debug'
make: *** [all] Error 2

/usr/bin/cmake-E cmake\u link\u脚本CMakeFiles/DemoServer.dir/link.txt--verbose=1
/usr/bin/c++-fPIC CMakeFiles/DemoServer.dir/stdafx.cpp.o CMakeFiles/DemoServer.dir/DemoServer.cpp.o-o DemoServer-rdynamic-lcombase-lNetWork-lMessageDispatch
/usr/local/lib/libMessageDispatch.a（Message_Facade.cpp.o）：在函数'Message_Facade:：stop（）'中：
/home/cl/server/ddsvn/MessageDispatch/Message_Facade.cpp:80:对'Timer_Queue:：instance（）的未定义引用
/home/cl/server/ddsvn/MessageDispatch/Message_Facade.cpp:80:对'Timer_Queue:：stop（）的未定义引用
/usr/local/lib/libMessageDispatch.a（Message_Facade.cpp.o）：在函数'Message_Facade:：wait（）'中：
/home/cl/server/ddsvn/MessageDispatch/Message_Facade.cpp:87:未定义对“Task:：wait（）”的引用
/home/cl/server/ddsvn/MessageDispatch/Message_Facade.cpp:88:未定义对“Task:：wait（）”的引用
/usr/local/lib/libMessageDispatch.a（Acceptor\u Manager.cpp.o）：在函数“Stream\u Acceptor”中：
/home/cl/server/ddsvn/MessageDispatch/。/NetWork/Stream\u Acceptor.h:40:未定义对“vtable for Stream\u Acceptor”的引用
/usr/local/lib/libMessageDispatch.a（Channel\u Manager.cpp.o）：在函数“Channel\u Manager”中：
/home/cl/server/ddsvn/MessageDispatch/Channel\u Manager.cpp:81:对“Channel\u Handler:：~Channel\u Handler（）”的未定义引用
/usr/local/lib/libMessageDispatch.a（Channel\u Manager.cpp.o）：在函数“~Channel\u Manager”中：
/home/cl/server/ddsvn/MessageDispatch/Channel\u Manager.cpp:86:对“Channel\u Handler:：~Channel\u Handler（）”的未定义引用
/home/cl/server/ddsvn/MessageDispatch/Channel\u Manager.cpp:86:对“Channel\u Handler:：~Channel\u Handler（）”的未定义引用
/usr/local/lib/libMessageDispatch.a（Channel\u Manager.cpp.o）：在函数“Channel\u Handler”中：
/home/cl/server/ddsvn/MessageDispatch/。/NetWork/Channel\u Handler.h:14:对“Channel\u Handler的vtable”的未定义引用
/usr/local/lib/libMessageDispatch.a（Channel_Manager.cpp.o）：（.rodata._ZTI15Channel_Manager[typeinfo for Channel_Manager]+0x28）：对“typeinfo for Channel_Handler”的未定义引用
/usr/local/lib/libMessageDispatch.a（Message.cpp.o）：在函数“Message”中：
/home/cl/server/ddsvn/MessageDispatch/Message.cpp:49:对“二进制\u流：：二进制\u流（int）”的未定义引用
/home/cl/server/ddsvn/MessageDispatch/Message.cpp:98:对'Binary\u Stream:：~Binary\u Stream（）'的未定义引用
/home/cl/server/ddsvn/MessageDispatch/Message.cpp:100:Binary\u Stream:：Binary\u Stream（int）的未定义引用
/usr/local/lib/libMessageDispatch.a（Message.cpp.o）：在函数“Message:：resize（int）”中：
/home/cl/server/ddsvn/MessageDispatch/Message.cpp:187:未定义对“Stream_Base:：resize（int）”的引用
/home/cl/server/ddsvn/MessageDispatch/Message.cpp:196:未定义对“Stream_Base:：resize（int）”的引用
/usr/local/lib/libMessageDispatch.a（Message.cpp.o）：在函数`~Message'中：
/home/cl/server/ddsvn/MessageDispatch/Message.cpp:203:对'Binary\u Stream:：~Binary\u Stream（）'的未定义引用
/home/cl/server/ddsvn/MessageDispatch/Message.cpp:203:对'Binary\u Stream:：~Binary\u Stream（）'的未定义引用
/usr/local/lib/libMessageDispatch.a（Message.cpp.o）：（.rodata.\u ZTV7Message[vtable for Message]+0x20）：对“Stream\u Base:：clone\u Stream（）”的未定义引用
/usr/local/lib/libMessageDispatch.a（Message.cpp.o）：（.rodata.\u ZTI7Message[typeinfo for Message]+0x10）：对“typeinfo for Binary\u Stream”的未定义引用
/usr/local/lib/libMessageDispatch.a（Connector\u Manager.cpp.o）：在函数“Stream\u Connector”中：
/home/cl/server/ddsvn/MessageDispatch/。/NetWork/Stream_Connector.h:42:对“vtable for Stream_Connector”的未定义引用
/usr/local/lib/libMessageDispatch.a（Context.cpp.o）：在函数“Context”中：
/home/cl/server/ddsvn/MessageDispatch/Context.cpp:15:未定义对“Dispatch\u Thread:：Dispatch\u Thread（）”的引用
/usr/local/lib/libMessageDispatch.a（Context.cpp.o）：在函数“Context:：initialize（）”中：
/home/cl/server/ddsvn/MessageDispatch/Context.cpp:113:对'Timer_Queue:：instance（）的未定义引用
/home/cl/server/ddsvn/MessageDispatch/Context.cpp:113:对'Timer_Queue:：start（）'的未定义引用
/home/cl/server/ddsvn/MessageDispatch/Context.cpp:116:未定义对“Task:：activate（int，int*）”的引用
/home/cl/server/ddsvn/MessageDispatch/Context.cpp:121:Task:：activate（int，int*）的未定义引用
/usr/local/lib/libMessageDispatch.a（Re_Connect_Handler.cpp.o）：在函数“Re_Connect_Handler:：process_Re_Connect（Context&，int）”中：
/home/cl/server/ddsvn/MessageDispatch/Re_Connect_Handler.cpp:23:对'Timer_Queue:：instance（）的未定义引用
/home/cl/server/ddsvn/MessageDispatch/Re_Connect_Handler.cpp:23：未定义对“计时器队列：：调度计时器（Smart_Ptr，Time_Value const&，Smart_Ptr，EDispatchType，调度线程*）的引用”
/usr/local/lib/libMessageDispatch.a（IO_-Thread.cpp.o）：在函数'IO_-Thread'中：
/home/cl/server/ddsvn/MessageDispatch/IO_Thread.cpp:4:对“Task:：Task（）”的未定义引用
/home/cl/server/ddsvn/MessageDispatch/IO_Thread.cpp:7:对“Task:：~Task（）”的未定义引用
/usr/local/lib/libMessageDispatch.a（IO_-Thread.cpp.o）：在函数`~IO_-Thread'中：
/home/cl/server/ddsvn/MessageDispatch/IO_Thread.cpp:12:对“Task:：~Task（）”的未定义引用
/home/cl/server/ddsvn/MessageDispatch/IO_Thread.cpp:12:对“Task:：~Task（）”的未定义引用
/usr/local/lib/libMessageDispatch.a（IO_Thread.cpp.o）：（.rodata._ZTI9IO_Thread[IO_Thread的类型信息]+0x10）：对“任务的类型信息”的未定义引用
collect2:ld返回了1个退出状态
生成[2]：***[DemoServer]错误1
make[2]：离开目录“/home/cl/server/ddsvn/DemoServer/Debug”
生成[1]：***[CMakeFiles/DemoServer.dir/all]错误2
make[1]：离开direc
AUX_SOURCE_DIRECTORY(. LIB_SRC_LIST)
ADD_LIBRARY(CommBase SHARED STATIC ${LIB_SRC_LIST})

INCLUDE_DIRECTORIES(../boost)
INSTALL(TARGETS CommBase CommBase
LIBRARY DESTINATION lib
ARCHIVE DESTINATION lib)

SET( CMAKE_BUILD_TYPE Debug )
SET(CMAKE_CXX_FLAGS_DEBUG "$ENV{CXXFLAGS} -O0 -Wall -g -ggdb")
SET(CMAKE_CXX_FLAGS_RELEASE "$ENV{CXXFLAGS} -O3 -Wall")

AUX_SOURCE_DIRECTORY(. LIB_SRC_LIST)
ADD_LIBRARY(NetWork SHARED STATIC ${LIB_SRC_LIST})

INCLUDE_DIRECTORIES(../boost)
INSTALL(TARGETS NetWork NetWork
LIBRARY DESTINATION lib
ARCHIVE DESTINATION lib)
 TARGET_LINK_LIBRARIES(NetWork CommBase)
SET( CMAKE_BUILD_TYPE Debug )
SET(CMAKE_CXX_FLAGS_DEBUG "$ENV{CXXFLAGS} -O0 -Wall -g -ggdb")
SET(CMAKE_CXX_FLAGS_RELEASE "$ENV{CXXFLAGS} -O3 -Wall")

AUX_SOURCE_DIRECTORY(. LIB_SRC_LIST)
ADD_LIBRARY(MessageDispatch SHARED STATIC ${LIB_SRC_LIST})

INCLUDE_DIRECTORIES(../boost)
INCLUDE_DIRECTORIES(../CommBase)
INCLUDE_DIRECTORIES(../NetWork)
ADD_DEPENDENCIES(MessageDispatch CommBase NetWork)
LINK_DIRECTORIES(/home/cl/server/ddsvn/debug)
TARGET_LINK_LIBRARIES(MessageDispatch CommBase NetWork)
INSTALL(TARGETS MessageDispatch MessageDispatch
LIBRARY DESTINATION lib
ARCHIVE DESTINATION lib)

PROJECT(DDLIB)
CMAKE_MINIMUM_REQUIRED(VERSION 2.6)
MESSAGE(STATUS "This is PROJECT_BINARY_DIR dir "${PROJECT_BINARY_DIR})
SET(LIBRARY_OUTPUT_PATH ${PROJECT_BINARY_DIR})
SET(EXECUTABLE_OUTPUT_PATH ${PROJECT_BINARY_DIR})
AUX_SOURCE_DIRECTORY(. SRC_LIST)
ADD_EXECUTABLE(DemoServer ${SRC_LIST})
INCLUDE_DIRECTORIES(../boost)
INCLUDE_DIRECTORIES(../CommBase)
INCLUDE_DIRECTORIES(../NetWork)
INCLUDE_DIRECTORIES(../MessageDispatch)
ADD_DEPENDENCIES(DemoServer CommBase NetWork MessageDispatch)
LINK_DIRECTORIES(/home/cl/server/ddsvn/debug)
TARGET_LINK_LIBRARIES(DemoServer CommBase NetWork MessageDispatch)

/usr/bin/cmake -E cmake_link_script CMakeFiles/DemoServer.dir/link.txt --verbose=1
/usr/bin/c++     -fPIC CMakeFiles/DemoServer.dir/stdafx.cpp.o CMakeFiles/DemoServer.dir/DemoServer.cpp.o  -o DemoServer -rdynamic -lCommBase -lNetWork -lMessageDispatch 
/usr/local/lib/libMessageDispatch.a(Message_Facade.cpp.o): In function `Message_Facade::stop()':
/home/cl/server/ddsvn/MessageDispatch/Message_Facade.cpp:80: undefined reference to `Timer_Queue::instance()'
/home/cl/server/ddsvn/MessageDispatch/Message_Facade.cpp:80: undefined reference to `Timer_Queue::stop()'
/usr/local/lib/libMessageDispatch.a(Message_Facade.cpp.o): In function `Message_Facade::wait()':
/home/cl/server/ddsvn/MessageDispatch/Message_Facade.cpp:87: undefined reference to `Task::wait()'
/home/cl/server/ddsvn/MessageDispatch/Message_Facade.cpp:88: undefined reference to `Task::wait()'
/usr/local/lib/libMessageDispatch.a(Acceptor_Manager.cpp.o): In function `Stream_Acceptor':
/home/cl/server/ddsvn/MessageDispatch/../NetWork/Stream_Accecptor.h:40: undefined reference to `vtable for Stream_Acceptor'
/usr/local/lib/libMessageDispatch.a(Channel_Manager.cpp.o): In function `Channel_Manager':
/home/cl/server/ddsvn/MessageDispatch/Channel_Manager.cpp:81: undefined reference to `Channel_Handler::~Channel_Handler()'
/usr/local/lib/libMessageDispatch.a(Channel_Manager.cpp.o): In function `~Channel_Manager':
/home/cl/server/ddsvn/MessageDispatch/Channel_Manager.cpp:86: undefined reference to `Channel_Handler::~Channel_Handler()'
/home/cl/server/ddsvn/MessageDispatch/Channel_Manager.cpp:86: undefined reference to `Channel_Handler::~Channel_Handler()'
/usr/local/lib/libMessageDispatch.a(Channel_Manager.cpp.o): In function `Channel_Handler':
/home/cl/server/ddsvn/MessageDispatch/../NetWork/Channel_Handler.h:14: undefined reference to `vtable for Channel_Handler'
/usr/local/lib/libMessageDispatch.a(Channel_Manager.cpp.o):(.rodata._ZTI15Channel_Manager[typeinfo for Channel_Manager]+0x28): undefined reference to `typeinfo for Channel_Handler'
/usr/local/lib/libMessageDispatch.a(Message.cpp.o): In function `Message':
/home/cl/server/ddsvn/MessageDispatch/Message.cpp:49: undefined reference to `Binary_Stream::Binary_Stream(int)'
/home/cl/server/ddsvn/MessageDispatch/Message.cpp:98: undefined reference to `Binary_Stream::~Binary_Stream()'
/home/cl/server/ddsvn/MessageDispatch/Message.cpp:100: undefined reference to `Binary_Stream::Binary_Stream(int)'
/usr/local/lib/libMessageDispatch.a(Message.cpp.o): In function `Message::resize(int)':
/home/cl/server/ddsvn/MessageDispatch/Message.cpp:187: undefined reference to `Stream_Base::resize(int)'
/home/cl/server/ddsvn/MessageDispatch/Message.cpp:196: undefined reference to `Stream_Base::resize(int)'
/usr/local/lib/libMessageDispatch.a(Message.cpp.o): In function `~Message':
/home/cl/server/ddsvn/MessageDispatch/Message.cpp:203: undefined reference to `Binary_Stream::~Binary_Stream()'
/home/cl/server/ddsvn/MessageDispatch/Message.cpp:203: undefined reference to `Binary_Stream::~Binary_Stream()'
/usr/local/lib/libMessageDispatch.a(Message.cpp.o):(.rodata._ZTV7Message[vtable for Message]+0x20): undefined reference to `Stream_Base::clone_stream()'
/usr/local/lib/libMessageDispatch.a(Message.cpp.o):(.rodata._ZTI7Message[typeinfo for Message]+0x10): undefined reference to `typeinfo for Binary_Stream'
/usr/local/lib/libMessageDispatch.a(Connector_Manager.cpp.o): In function `Stream_Connector':
/home/cl/server/ddsvn/MessageDispatch/../NetWork/Stream_Connector.h:42: undefined reference to `vtable for Stream_Connector'
/usr/local/lib/libMessageDispatch.a(Context.cpp.o): In function `Context':
/home/cl/server/ddsvn/MessageDispatch/Context.cpp:15: undefined reference to `Dispatch_Thread::Dispatch_Thread()'
/usr/local/lib/libMessageDispatch.a(Context.cpp.o): In function `Context::initialize()':
/home/cl/server/ddsvn/MessageDispatch/Context.cpp:113: undefined reference to `Timer_Queue::instance()'
/home/cl/server/ddsvn/MessageDispatch/Context.cpp:113: undefined reference to `Timer_Queue::start()'
/home/cl/server/ddsvn/MessageDispatch/Context.cpp:116: undefined reference to `Task::activate(int, int*)'
/home/cl/server/ddsvn/MessageDispatch/Context.cpp:121: undefined reference to `Task::activate(int, int*)'
/usr/local/lib/libMessageDispatch.a(Re_Connect_Handler.cpp.o): In function `Re_Connect_Handler::process_re_connect(Context&, int)':
/home/cl/server/ddsvn/MessageDispatch/Re_Connect_Handler.cpp:23: undefined reference to `Timer_Queue::instance()'
/home/cl/server/ddsvn/MessageDispatch/Re_Connect_Handler.cpp:23: undefined reference to `Timer_Queue::schedule_timer(Smart_Ptr<Timer_Handler>, Time_Value const&, Smart_Ptr<Ref_Object>, EDispatchType, Dispatch_Thread*)'
/usr/local/lib/libMessageDispatch.a(IO_Thread.cpp.o): In function `IO_Thread':
/home/cl/server/ddsvn/MessageDispatch/IO_Thread.cpp:4: undefined reference to `Task::Task()'
/home/cl/server/ddsvn/MessageDispatch/IO_Thread.cpp:7: undefined reference to `Task::~Task()'
/usr/local/lib/libMessageDispatch.a(IO_Thread.cpp.o): In function `~IO_Thread':
/home/cl/server/ddsvn/MessageDispatch/IO_Thread.cpp:12: undefined reference to `Task::~Task()'
/home/cl/server/ddsvn/MessageDispatch/IO_Thread.cpp:12: undefined reference to `Task::~Task()'
/usr/local/lib/libMessageDispatch.a(IO_Thread.cpp.o):(.rodata._ZTI9IO_Thread[typeinfo for IO_Thread]+0x10): undefined reference to `typeinfo for Task'
collect2: ld returned 1 exit status
make[2]: *** [DemoServer] Error 1
make[2]: Leaving directory `/home/cl/server/ddsvn/DemoServer/Debug'
make[1]: *** [CMakeFiles/DemoServer.dir/all] Error 2
make[1]: Leaving directory `/home/cl/server/ddsvn/DemoServer/Debug'
make: *** [all] Error 2

TARGET_LINK_LIBRARIES(DemoServer MessageDispatch NetWork CommBase)