C++ 调用程序中对库类成员的未定义引用错误_C++_Cross Platform_Shared Libraries_Undefined Reference

C++ 调用程序中对库类成员的未定义引用错误

c++

C++ 调用程序中对库类成员的未定义引用错误,c++,cross-platform,shared-libraries,undefined-reference,C++,Cross Platform,Shared Libraries,Undefined Reference,以下新增问题，2011年11月4日我正在开发一个跨平台的共享库DLLS/SOS和TealC++程序，虽然我必须能够支持C。这些库只作为目标代码，但是测试程序会与源一起传送，这样我们的客户可以有示例代码。出于这个原因，我正在设计要在运行时加载的库，即使用dlopen（）/LoadLibraryA（）进行动态链接我在Umbutu 10.04上使用g++4.4.3-4，在Vista/64上使用VC++2008（32位模式）在Windows上（现在）一切似乎都很好。然而，当我在Linux上编译时，

以下新增问题，2011年11月4日

<>我正在开发一个跨平台的共享库DLLS/SOS和TealC++程序，虽然我必须能够支持C。这些库只作为目标代码，但是测试程序会与源一起传送，这样我们的客户可以有示例代码。出于这个原因，我正在设计要在运行时加载的库，即使用dlopen（）/LoadLibraryA（）进行动态链接

我在Umbutu 10.04上使用g++4.4.3-4，在Vista/64上使用VC++2008（32位模式）

在Windows上（现在）一切似乎都很好。然而，当我在Linux上编译时，我得到了一些我无法理解的错误

测试仪和库中有几个用.cpp和.h编码的类。库中的类和除主入口点之外的大部分内容都位于名称空间中

以下是该项目的简要示意图：

首先，我承认，我缩短了一堆名字，这样代码就更可读了

discover.cpp

创建一个类对象，该类对象带有指向它的指针，称为DiscoverObject类型的主对象
具有一个外部“C”函数，该函数将主对象作为void*返回给调用程序
DiscoverObject有几个方法，并实例化在单独的cpp和.h中找到的其他类。一个特殊的方法名为Hello（），它完成了您所期望的功能，它打印一条“Hello”测试消息

测试仪.cpp

获取库的句柄
获取指向返回主对象的函数的函数指针
执行函数（指针）并将返回的地址从void*强制转换为DISCOVER\NS:：DiscoverObject*aDiscoverObject
运行aDiscoverObject->Hello（）

我编译时使用：

CC=@g++

gflags=-g3

cflags=-fPIC-Wall-pedantic

lib_linkflags:=-shared-fPIC-lstdc++-lrt-lpthread-rdynamic

测试仪链接标志：=-ldl-lpthread

defines=-D\u linux\ud\u DEBUG-D\u IPC\u ARCH\u INTEL=1-D\u THREAD\u SAFE

现在，当我编译时，会出现以下错误： *Tester.cpp:142:Discover\NS:：DiscoverObject:：hello（）的未定义引用*

我还从discover中获得了一系列其他未定义的引用错误。例如： *discover.so:discover\n NS:：DeviceList:：~DeviceList（）的未定义引用*

我尝试过用所谓的外部“C”来制作几乎所有的东西。没有区别

我尝试将语句放入discover.cpp，如下所示： extern void Discover_NS:：OtherClass:：method（args）；但这给了我关于“类外声明不是定义”错误的错误

我知道看到代码会有帮助，但我需要时间来找出一些小东西来发布

有人能提出解决这一混乱局面的办法吗

谢谢

韦斯

Dmitry的解决方案并不是全部修复方案，而是解决方案中的一个必要元素。在检查我的makefile时，我发现了一些无意中重复的行，我删除了这些行，还有两个“输入错误”，其中-o的路径被错误地编码到编译步骤中。logger.cpp和RemeException.cpp编译的中断步骤：

./common/logger.o : ./common/logger.cpp
    $(CC) $(gflags)  $(cflags) -c  $(defines)  -I ./common  
        -I ./EdgeIO  -I ./Discover   
        -o ./common/Debug/logger.o   <+++++++++ path to .o was wrong
        ./common/logger.cpp   2>&1  | tee ./RemKonTester/logger.ERR

我从Eclipse获得了相同的错误消息集

RemKonTester.cpp包括声明这些项目的所有.h。我已经用声明extern“C”试过了，没有

希望得到帮助

韦斯

编辑：终于找到了“编辑”。让它更漂亮。wjm

抱歉耽搁了。昨晚我不得不把一棵倒下的树从我的前院弄出来

注意：我更改了原始注释中的一些名称，使其更短。这个答案把一切都说清楚了

g++输出

$ make
./EdgeIO/dllMain.cpp: In function ‘void InitalizeLibraryServices()’:
./EdgeIO/dllMain.cpp:158: warning: unused variable ‘pi’
./Discover/dllmain.cpp: In function ‘void InitalizeLibraryServices()’:
./Discover/dllmain.cpp:174: warning: unused variable ‘pi’
./RemKonTester/RemKonTester.cpp: In function ‘int main(int, char**)’:
./RemKonTester/RemKonTester.cpp:130: warning: ISO C++ forbids casting between     
pointer-to-function and pointer-to-object
./RemKonTester/RemKonTester.cpp:152: warning: unused variable ‘searchResp’
./RemKonTester/libraryClass.cpp: In member function ‘int 
library::AttachLibrary()’:
./RemKonTester/libraryClass.cpp:132: warning: ISO C++ forbids casting between 
pointer-to-function and pointer-to-object
./RemKonTester/libraryClass.cpp:154: warning: ISO C++ forbids casting between 
pointer-to-function and pointer-to-object
./RemKonTester/Debug/RemKonTester.o: In function `main': 
/home/wmiller/Projects/Eclipse/
./RemKonTester/RemKonTester.cpp:142: undefined reference to 
`RemKon_Discover::DiscoverObject::hello()'
collect2: ld returned 1 exit status
gflags = -g3
tstlinkflags = -ldl  -lpthread
defines =  -D__linux__   -D_DEBUG   -D_IPC_ARCH_INTEL=1   -D_THREAD_SAFE
./Debug/libdiscover.so: undefined reference to     
`RemKon_Discover::RemKonDeviceList::~RemKonDeviceList()'
./Debug/libdiscover.so: undefined reference to 
`RemKon_Discover::RemSocket::ClientPort(unsigned short)'
./Debug/libdiscover.so: undefined reference to 
`RemKon_Discover::RemSocket::PayloadSize(unsigned int)'
./Debug/libdiscover.so: undefined reference to 
`RemKon_Discover::RemSocket::Socket() const'
./Debug/libdiscover.so: undefined reference to 
`RemKon_Discover::RemKonDeviceList::Count() const'
./Debug/libdiscover.so: undefined reference to 
`RemKon_Discover::RemException::~RemException()'
./Debug/libdiscover.so: undefined reference to 
`RemKon_Discover::RemSocket::UDPbinder()'
./Debug/libdiscover.so: undefined reference to 
`RemKon_Discover::RemSocket::ListenTimeOut(int)'
./Debug/libdiscover.so: undefined reference to 
`RemKon_Discover::RemSocket::ServerPort(unsigned short)'
./Debug/libdiscover.so: undefined reference to 
`RemKon_Discover::RemKonDeviceList::Next()'
./Debug/libdiscover.so: undefined reference to `RemKon_Discover::Log(char 
const*, ...)'
./Debug/libdiscover.so: undefined reference to 
`RemKon_Discover::RemSocket::UDPlisten(unsigned char*, int*, sockaddr_in*, int*)'
./Debug/libdiscover.so: undefined reference to 
`RemKon_Discover::RemException::RemException()'
./Debug/libdiscover.so: undefined reference to `RemKon_Discover::VerboseLogging()'
./Debug/libdiscover.so: undefined reference to 
`RemKon_Discover::RemSocket::RegisterCallbackFunction(void (*)(void*, unsigned 
char*, int), void*)'
./Debug/libdiscover.so: undefined reference to 
`RemKon_Discover::RemKonDeviceList::First()'
./Debug/libdiscover.so: undefined reference to 
`RemKon_Discover::RemSocket::TestData(unsigned int, unsigned int, unsigned char*, 
unsigned int)'
./Debug/libdiscover.so: undefined reference to `RemKon_Discover::Logging()'
./Debug/libdiscover.so: undefined reference to 
`RemKon_Discover::RemSocket::MessageLength(int)'
./Debug/libdiscover.so: undefined reference to 
`RemKon_Discover::RemSocket::LocalIpAddress(int)'
./Debug/libdiscover.so: undefined reference to 
`RemKon_Discover::RemSocket::UDPsend()'
./Debug/libdiscover.so: undefined reference to 
`RemKon_Discover::DiscoverObject::LocalIpAddress() const'
./Debug/libdiscover.so: undefined reference to 
`RemKon_Discover::RemSocket::SetBroadcastMode()'
./Debug/libdiscover.so: undefined reference to 
`RemKon_Discover::MakeMacAddressString(unsigned char*, char*)'
./Debug/libdiscover.so: undefined reference to 
`RemKon_Discover::RemKonDeviceList::RemKonDeviceList()'
./Debug/libdiscover.so: undefined reference to 
`RemKon_Discover::RemKonDeviceList::New()'
./Debug/libdiscover.so: undefined reference to 
`RemKon_Discover::ActivateLogging(unsigned int)'
./Debug/libdiscover.so: undefined reference to 
`RemKon_Discover::RemSocket::RemSocket()'
./Debug/libdiscover.so: undefined reference to 
`RemKon_Discover::RemSocket::Payload(unsigned int)'
collect2: ld returned 1 exit status

这是makefile。抱歉，我不太会说make，所以makefile是功能性的，不美观

CC = @g++
gflags = -g3
cflags = -fPIC -Wall -pedantic
liblinkflags := -shared -fPIC -lstdc++ -lrt -lpthread -rdynamic
tstlinkflags := -ldl  -lpthread
defines = -D__linux__   -D_DEBUG   -D_IPC_ARCH_INTEL=1   -D_THREAD_SAFE


all : clean edgeio discover tester


############################################

edgeio : ./EdgeIO/dllMain.o ./EdgeIO/EdgeIO.o
$(CC) $(gflags)  $(liblinkflags) $(defines)    -Wl,-soname,./Debug
    /libedgeio.so.1  -o ./Debug/libedgeio.so.1.0 ./EdgeIO/Debug/edgeio.o  
    ./EdgeIO/Debug/dllmain.o    2>&1  | tee ./EdgeIO/make.ERR
            @cd ./Debug; ln -sf libedgeio.so.1.0    libedgeio.so
        @cd ./Debug; ln -sf libedgeio.so.1.0    libedgeio.so.1

./EdgeIO/dllMain.o : ./EdgeIO/dllMain.cpp
        $(CC) $(gflags)  $(cflags) -c $(defines)   -I ./common  -I ./EdgeIO  
    -I ./Discover   -o./EdgeIO/Debug/dllmain.o  ./EdgeIO/dllMain.cpp   2>&1  
    | tee ./EdgeIO/dllmain.ERR

./EdgeIO/EdgeIO.o : ./EdgeIO/EdgeIO.cpp
    $(CC) $(gflags)  $(cflags) -c $(defines)   -I ./common  -I ./EdgeIO  
    -I ./Discover   -o./EdgeIO/Debug/edgeio.o  ./EdgeIO/EdgeIO.cpp     2>&1  | 
    tee ./EdgeIO/EdgeIO.ERR

############################################

discover : ./Discover/Discover.o ./Discover/dllmain.o
    $(CC) $(gflags)  $(liblinkflags) $(defines)    -Wl,-soname,./Debug
        /libdiscover.so.1  -o ./Debug/libdiscover.so.1.0          ./Discover/Debug
        /Discover.o  ./Discover/Debug/dllmain.o    2>&1  | tee ./Discover/make.ERR
    @cd ./Debug; ln -sf libdiscover.so.1.0  libdiscover.so
    @cd ./Debug; ln -sf libdiscover.so.1.0  libdiscover.so.1

./Discover/Discover.o : ./Discover/Discover.cpp
    $(CC) $(gflags)  $(cflags) -c $(defines)   -I ./common  -I ./EdgeIO  
    -I ./Discover   -o./Discover/Debug/Discover.o  ./Discover/Discover.cpp  
     2>&1  | tee ./Discover/Discover.ERR

./Discover/dllmain.o : ./Discover/dllmain.cpp
        $(CC) $(gflags)  $(cflags) -c  $(defines)  -I ./common  -I ./EdgeIO  
        -I ./Discover   -o./Discover/Debug/dllmain.o  ./Discover/dllmain.cpp   
        2>&1  | tee ./Discover/dllmain.ERR

############################################

tester : ./RemKonTester/RemKonTester.o ./common/logger.o  ./RemKonTester
        /libraryClass.o    ./common/RemException.o
    $(CC)  $(gflags)  $(tstlinkflags) $(defines)       
        -L ./Debug -o ./Debug/RemKonTester  ./RemKonTester/Debug
        /RemKonTester.o  ./RemKonTester/Debug/logger.o  ./RemKonTester/Debug
        /libraryClass.o   2>&1  | tee ./RemKonTester/make.ERR

    @echo "gflags = $(gflags)"   2>&1  | tee ./RemKonTester/make.ERR
    @echo "tstlinkflags = $(tstlinkflags)"   2>&1  | tee ./RemKonTester/make.ERR
    @echo "defines =  $(defines)"   2>&1  | tee ./RemKonTester/make.ERR

    $(CC)  $(gflags)  $(tstlinkflags) $(defines)      -L ./Debug    -ldiscover   
        -ledgeio -o ./Debug/RemKonTester  ./RemKonTester/Debug/RemKonTester.o  
        ./RemKonTester/Debug/logger.o  ./RemKonTester/Debug/libraryClass.o   
        2>&1  | tee ./RemKonTester/make.ERR

./RemKonTester/RemKonTester.o : ./RemKonTester/RemKonTester.cpp
    $(CC) $(gflags)  $(cflags) -c $(defines)   -I ./common  -I ./EdgeIO  
        -I ./Discover   -o ./RemKonTester/Debug/RemKonTester.o   ./RemKonTester
        /RemKonTester.cpp   2>&1  | tee ./RemKonTester/RemKonTester.ERR

./common/logger.o : ./common/logger.cpp
    $(CC) $(gflags)  $(cflags) -c  $(defines)  -I ./common  -I ./EdgeIO  
        -I ./Discover    -o ./RemKonTester/Debug/logger.o  ./common/logger.cpp
        2>&1  | tee ./RemKonTester/logger.ERR

./RemKonTester/libraryClass.o : ./RemKonTester/libraryClass.cpp
    $(CC) $(gflags)  $(cflags) -c  $(defines)  -I ./common  -I ./EdgeIO  
        -I ./Discover    -o ./RemKonTester/Debug/libraryClass.o 
        ./RemKonTester/libraryClass.cpp   2>&1  | tee ./RemKonTester
        /libraryClass.ERR

./common/RemException.o : ./common/RemException.cpp
    $(CC) $(gflags)  $(cflags) -c  $(defines)  -I ./common  -I ./EdgeIO  
        -I ./Discover    -o ./RemKonTester/Debug/RemException.o ./common
        /RemException.cpp   2>&1  | tee ./RemKonTester/RemException.ERR


############################################

clean :
    @rm -f *.ERR
    @rm -f ./common/*.ERR
    @rm -f ./EdgeIO/*.ERR
    @rm -f ./Discover/*.ERR
    @rm -f ./RemKonTester/*.ERR

    @rm -f QEMACRO*
    @rm -f ./common/EdgeIO/QEMACRO*
    @rm -f ./EdgeIO/QEMACRO*
    @rm -f ./Discover/QEMACRO*
    @rm -f ./RemKonTester/QEMACRO*

    @rm -f ./Debug/*.o
    @rm -f ./common/Debug/*.o
    @rm -f ./EdgeIO/Debug/*.o
    @rm -f ./Discover/Debug/*.o
    @rm -f ./RemKonTester/Debug/*.o

    @rm -f ./Debug/*.log
    @rm -f ./common/Debug/*.log
    @rm -f ./EdgeIO/Debug/*.log
    @rm -f ./Discover/Debug/*.log
    @rm -f ./RemKonTester/Debug/*.log

    @rm -f ./Debug/*.so*

############################################

谢谢

Wes

您的问题似乎是

-l

的位置：

它们应该在对象文件之后，因为链接器在命令行遇到它们时加载它们，并搜索未定义的符号

有关更多信息，请参见

man-ld

（特别是

-l

选项）：

-l名称规范

链接器将只在命令行上指定的位置搜索存档一次。如果存档定义了在命令行存档之前出现的某个对象中未定义的符号，链接器将包括存档中的适当文件。但是，稍后出现在命令行上的对象中的未定义符号不会导致重新搜索存档的链接器

这应该适合您：

$（CC）$（gflags）$（tstlinkflags）$（定义）-L./Debug-o./Debug/RemKonTester./RemKonTester/Debug/RemKonTester.o./RemKonTester/Debug/logger.o./RemKonTester/Debug/libraryClass.o-ldiscover-legio2>&1 | tee./RemKonTester/make.ERR

请注意，StackOverflow中有一个编辑问题的选项，将其他信息作为答案发布不是一个好做法。

您可以发布g++的实际输出吗？通常问题是在给g++的参数的顺序上。同样，给g++的具体参数也不是很清楚：）请尝试

make-n

查看make执行的实际g++命令，并将它们发布到此处。还可以使用

nm lib\u your\u lib进行检查。因此，在\u you\u lib

中添加一些\u symbol\u，以确保预期的符号实际上在库中

CC = @g++
gflags = -g3
cflags = -fPIC -Wall -pedantic
liblinkflags := -shared -fPIC -lstdc++ -lrt -lpthread -rdynamic
tstlinkflags := -ldl  -lpthread
defines = -D__linux__   -D_DEBUG   -D_IPC_ARCH_INTEL=1   -D_THREAD_SAFE


all : clean edgeio discover tester


############################################

edgeio : ./EdgeIO/dllMain.o ./EdgeIO/EdgeIO.o
$(CC) $(gflags)  $(liblinkflags) $(defines)    -Wl,-soname,./Debug
    /libedgeio.so.1  -o ./Debug/libedgeio.so.1.0 ./EdgeIO/Debug/edgeio.o  
    ./EdgeIO/Debug/dllmain.o    2>&1  | tee ./EdgeIO/make.ERR
            @cd ./Debug; ln -sf libedgeio.so.1.0    libedgeio.so
        @cd ./Debug; ln -sf libedgeio.so.1.0    libedgeio.so.1

./EdgeIO/dllMain.o : ./EdgeIO/dllMain.cpp
        $(CC) $(gflags)  $(cflags) -c $(defines)   -I ./common  -I ./EdgeIO  
    -I ./Discover   -o./EdgeIO/Debug/dllmain.o  ./EdgeIO/dllMain.cpp   2>&1  
    | tee ./EdgeIO/dllmain.ERR

./EdgeIO/EdgeIO.o : ./EdgeIO/EdgeIO.cpp
    $(CC) $(gflags)  $(cflags) -c $(defines)   -I ./common  -I ./EdgeIO  
    -I ./Discover   -o./EdgeIO/Debug/edgeio.o  ./EdgeIO/EdgeIO.cpp     2>&1  | 
    tee ./EdgeIO/EdgeIO.ERR

############################################

discover : ./Discover/Discover.o ./Discover/dllmain.o
    $(CC) $(gflags)  $(liblinkflags) $(defines)    -Wl,-soname,./Debug
        /libdiscover.so.1  -o ./Debug/libdiscover.so.1.0          ./Discover/Debug
        /Discover.o  ./Discover/Debug/dllmain.o    2>&1  | tee ./Discover/make.ERR
    @cd ./Debug; ln -sf libdiscover.so.1.0  libdiscover.so
    @cd ./Debug; ln -sf libdiscover.so.1.0  libdiscover.so.1

./Discover/Discover.o : ./Discover/Discover.cpp
    $(CC) $(gflags)  $(cflags) -c $(defines)   -I ./common  -I ./EdgeIO  
    -I ./Discover   -o./Discover/Debug/Discover.o  ./Discover/Discover.cpp  
     2>&1  | tee ./Discover/Discover.ERR

./Discover/dllmain.o : ./Discover/dllmain.cpp
        $(CC) $(gflags)  $(cflags) -c  $(defines)  -I ./common  -I ./EdgeIO  
        -I ./Discover   -o./Discover/Debug/dllmain.o  ./Discover/dllmain.cpp   
        2>&1  | tee ./Discover/dllmain.ERR

############################################

tester : ./RemKonTester/RemKonTester.o ./common/logger.o  ./RemKonTester
        /libraryClass.o    ./common/RemException.o
    $(CC)  $(gflags)  $(tstlinkflags) $(defines)       
        -L ./Debug -o ./Debug/RemKonTester  ./RemKonTester/Debug
        /RemKonTester.o  ./RemKonTester/Debug/logger.o  ./RemKonTester/Debug
        /libraryClass.o   2>&1  | tee ./RemKonTester/make.ERR

    @echo "gflags = $(gflags)"   2>&1  | tee ./RemKonTester/make.ERR
    @echo "tstlinkflags = $(tstlinkflags)"   2>&1  | tee ./RemKonTester/make.ERR
    @echo "defines =  $(defines)"   2>&1  | tee ./RemKonTester/make.ERR

    $(CC)  $(gflags)  $(tstlinkflags) $(defines)      -L ./Debug    -ldiscover   
        -ledgeio -o ./Debug/RemKonTester  ./RemKonTester/Debug/RemKonTester.o  
        ./RemKonTester/Debug/logger.o  ./RemKonTester/Debug/libraryClass.o   
        2>&1  | tee ./RemKonTester/make.ERR

./RemKonTester/RemKonTester.o : ./RemKonTester/RemKonTester.cpp
    $(CC) $(gflags)  $(cflags) -c $(defines)   -I ./common  -I ./EdgeIO  
        -I ./Discover   -o ./RemKonTester/Debug/RemKonTester.o   ./RemKonTester
        /RemKonTester.cpp   2>&1  | tee ./RemKonTester/RemKonTester.ERR

./common/logger.o : ./common/logger.cpp
    $(CC) $(gflags)  $(cflags) -c  $(defines)  -I ./common  -I ./EdgeIO  
        -I ./Discover    -o ./RemKonTester/Debug/logger.o  ./common/logger.cpp
        2>&1  | tee ./RemKonTester/logger.ERR

./RemKonTester/libraryClass.o : ./RemKonTester/libraryClass.cpp
    $(CC) $(gflags)  $(cflags) -c  $(defines)  -I ./common  -I ./EdgeIO  
        -I ./Discover    -o ./RemKonTester/Debug/libraryClass.o 
        ./RemKonTester/libraryClass.cpp   2>&1  | tee ./RemKonTester
        /libraryClass.ERR

./common/RemException.o : ./common/RemException.cpp
    $(CC) $(gflags)  $(cflags) -c  $(defines)  -I ./common  -I ./EdgeIO  
        -I ./Discover    -o ./RemKonTester/Debug/RemException.o ./common
        /RemException.cpp   2>&1  | tee ./RemKonTester/RemException.ERR


############################################

clean :
    @rm -f *.ERR
    @rm -f ./common/*.ERR
    @rm -f ./EdgeIO/*.ERR
    @rm -f ./Discover/*.ERR
    @rm -f ./RemKonTester/*.ERR

    @rm -f QEMACRO*
    @rm -f ./common/EdgeIO/QEMACRO*
    @rm -f ./EdgeIO/QEMACRO*
    @rm -f ./Discover/QEMACRO*
    @rm -f ./RemKonTester/QEMACRO*

    @rm -f ./Debug/*.o
    @rm -f ./common/Debug/*.o
    @rm -f ./EdgeIO/Debug/*.o
    @rm -f ./Discover/Debug/*.o
    @rm -f ./RemKonTester/Debug/*.o

    @rm -f ./Debug/*.log
    @rm -f ./common/Debug/*.log
    @rm -f ./EdgeIO/Debug/*.log
    @rm -f ./Discover/Debug/*.log
    @rm -f ./RemKonTester/Debug/*.log

    @rm -f ./Debug/*.so*

############################################

$(CC)  $(gflags)  $(tstlinkflags) $(defines)      -L ./Debug    -ldiscover   
        -ledgeio -o ./Debug/RemKonTester  ./RemKonTester/Debug/RemKonTester.o  
        ./RemKonTester/Debug/logger.o  ./RemKonTester/Debug/libraryClass.o   
        2>&1  | tee ./RemKonTester/make.ERR