MSDN中对于在不同的配置下Link的LIB作了说明:
C Runtime Library:
开关 |
对应的库 |
版本 |
/MD |
MSVCRT.LIB |
多线程DLL的Release版本 |
/MDd |
MSVCRTD.LIB |
多线程DLL的Debug版本 |
/MT |
LIBCMT.LIB |
多线程静态链接的Release版本 |
/MTd |
LIBCMTD.LIB |
多线程静态链接的Debug版本 |
/clr |
MSVCMRT.LIB |
托管代码和非托管代码混合 |
/clr:pure |
MSVCURT.LIB |
纯托管代码 |
C++ Standard Library:
开关 |
对应的库 |
版本 |
/MD |
MSVCPRT.LIB |
多线程DLL的Release版本 |
/MDd |
MSVCPRTD.LIB |
多线程DLL的Debug版本 |
/MT |
LIBCPMT.LIB |
多线程静态链接的Release版本 |
/MTd |
LIBCPMTD.LIB |
多线程静态链接的Debug版本 |
编译器会自动根据编译选项,选择对应的LIB文件。一般情况下这不会出现问题。
然而,在部分情况下,一旦你的程序的各个部分(LIB, OBJ…)并非由相同的编译选项编译出,而Link在一起的话,会出现各种各样的看似很难解决的问题,这类问题主要以重复定义的错误形式存在,通常的解决方法也很简单,就是选择同样的编译选项进行编译之后再Link。
之前刚下载了ANTLR,在准备编译它的Example的时候发现了下面的Build错误(我自己为这个例子创建了VS的项目,当前配置为动态链接Runtime库,Debug版):
1>msvcprtd.lib(MSVCP80D.dll) : error LNK2005: "public: __thiscall std::basic_string 1>msvcprtd.lib(MSVCP80D.dll) : error LNK2005: "public: class std::basic_string 1>msvcprtd.lib(MSVCP80D.dll) : error LNK2005: "public: void __thiscall std::basic_string 1>msvcprtd.lib(MSVCP80D.dll) : error LNK2005: "public: unsigned int __thiscall std::basic_string 1>msvcprtd.lib(MSVCP80D.dll) : error LNK2005: "public: class std::basic_string 1>msvcprtd.lib(MSVCP80D.dll) : error LNK2005: "public: __thiscall std::basic_string 1>msvcprtd.lib(MSVCP80D.dll) : error LNK2005: "public: char const & __thiscall std::basic_string 1>msvcprtd.lib(MSVCP80D.dll) : error LNK2005: "public: class std::basic_string 1>msvcprtd.lib(MSVCP80D.dll) : error LNK2005: "public: class std::basic_string 1>msvcprtd.lib(MSVCP80D.dll) : error LNK2005: "public: __thiscall std::basic_string 1>msvcprtd.lib(MSVCP80D.dll) : error LNK2005: "class std::basic_string 1>msvcprtd.lib(MSVCP80D.dll) : error LNK2005: "public: char const * __thiscall std::basic_string 1>msvcprtd.lib(MSVCP80D.dll) : error LNK2005: "bool __cdecl std::operator< 1>msvcprtd.lib(MSVCP80D.dll) : error LNK2005: "public: class std::basic_ostream 1>msvcprtd.lib(MSVCP80D.dll) : error LNK2005: "public: class std::basic_ostream 1>msvcprtd.lib(MSVCP80D.dll) : error LNK2005: "class std::basic_ostream 1>msvcprtd.lib(MSVCP80D.dll) : error LNK2005: "public: void __thiscall std::basic_ios 1>msvcprtd.lib(MSVCP80D.dll) : error LNK2005: "public: int __thiscall std::ios_base::width(int)" (?width@ios_base@std@@QAEHH@Z) already defined in antlr.lib(CharScanner.obj) 1>msvcprtd.lib(MSVCP80D.dll) : error LNK2005: "public: int __thiscall std::basic_streambuf 1>msvcprtd.lib(MSVCP80D.dll) : error LNK2005: "public: static bool __cdecl std::char_traits 1>msvcprtd.lib(MSVCP80D.dll) : error LNK2005: "public: static int __cdecl std::char_traits 1>msvcprtd.lib(MSVCP80D.dll) : error LNK2005: "public: int __thiscall std::basic_streambuf 1>msvcprtd.lib(MSVCP80D.dll) : error LNK2005: "public: class std::basic_streambuf 1>msvcprtd.lib(MSVCP80D.dll) : error LNK2005: "public: char __thiscall std::basic_ios 1>msvcprtd.lib(MSVCP80D.dll) : error LNK2005: "public: int __thiscall std::ios_base::flags(void)const " (?flags@ios_base@std@@QBEHXZ) already defined in antlr.lib(CharScanner.obj) 1>msvcprtd.lib(MSVCP80D.dll) : error LNK2005: "public: int __thiscall std::ios_base::width(void)const " (?width@ios_base@std@@QBEHXZ) already defined in antlr.lib(CharScanner.obj) 1>msvcprtd.lib(MSVCP80D.dll) : error LNK2005: "public: static unsigned int __cdecl std::char_traits 1>msvcprtd.lib(MSVCP80D.dll) : error LNK2005: "public: class std::basic_ostream 1>msvcprtd.lib(MSVCP80D.dll) : error LNK2005: "public: class std::basic_ostream 1>msvcprtd.lib(MSVCP80D.dll) : error LNK2005: "public: bool __thiscall std::ios_base::good(void)const " (?good@ios_base@std@@QBE_NXZ) already defined in antlr.lib(CharScanner.obj) 1>msvcprtd.lib(MSVCP80D.dll) : error LNK2005: "public: void __thiscall std::basic_ostream 1>msvcprtd.lib(MSVCP80D.dll) : error LNK2005: "public: void __thiscall std::basic_streambuf 1>msvcprtd.lib(MSVCP80D.dll) : error LNK2005: "public: void __thiscall std::basic_streambuf
1>msvcprtd.lib(MSVCP80D.dll) : error LNK2005: "class std::basic_ostream 1>libcpmt.lib(locale0.obj) : error LNK2005: "private: static class std::locale::_Locimp * __cdecl std::locale::_Getgloballocale(void)" (?_Getgloballocale@locale@std@@CAPAV_Locimp@12@XZ) already defined in msvcprtd.lib(MSVCP80D.dll) 1>libcpmt.lib(locale0.obj) : error LNK2005: "private: static void __cdecl std::locale::facet::facet_Register(class std::locale::facet *)" (?facet_Register@facet@locale@std@@CAXPAV123@@Z) already defined in msvcprtd.lib(MSVCP80D.dll) 1>libcpmt.lib(locale0.obj) : error LNK2005: "public: static void __cdecl std::_Locinfo::_Locinfo_dtor(class std::_Locinfo *)" (?_Locinfo_dtor@_Locinfo@std@@SAXPAV12@@Z) already defined in msvcprtd.lib(MSVCP80D.dll) 1>libcpmt.lib(locale0.obj) : error LNK2005: "public: static void __cdecl std::_Locinfo::_Locinfo_ctor(class std::_Locinfo *,char const *)" (?_Locinfo_ctor@_Locinfo@std@@SAXPAV12@PBD@Z) already defined in msvcprtd.lib(MSVCP80D.dll) 1>libcpmt.lib(xmutex.obj) : error LNK2005: "public: void __thiscall std::_Mutex::_Lock(void)" (?_Lock@_Mutex@std@@QAEXXZ) already defined in msvcprtd.lib(MSVCP80D.dll) 1>libcpmt.lib(xmutex.obj) : error LNK2005: "public: void __thiscall std::_Mutex::_Unlock(void)" (?_Unlock@_Mutex@std@@QAEXXZ) already defined in msvcprtd.lib(MSVCP80D.dll) 1>libcpmt.lib(xlock.obj) : error LNK2005: "public: __thiscall std::_Lockit::_Lockit(int)" (??0_Lockit@std@@QAE@H@Z) already defined in msvcprtd.lib(MSVCP80D.dll) 1>libcpmt.lib(xlock.obj) : error LNK2005: "public: __thiscall std::_Lockit::~_Lockit(void)" (??1_Lockit@std@@QAE@XZ) already defined in msvcprtd.lib(MSVCP80D.dll) 1>LIBCMT.lib(invarg.obj) : error LNK2005: __invoke_watson already defined in MSVCRTD.lib(MSVCR80D.dll) 1>LIBCMT.lib(invarg.obj) : error LNK2005: __invalid_parameter already defined in MSVCRTD.lib(MSVCR80D.dll) 1>LIBCMT.lib(setlocal.obj) : error LNK2005: __configthreadlocale already defined in MSVCRTD.lib(MSVCR80D.dll) 1>LIBCMT.lib(tidtable.obj) : error LNK2005: __encode_pointer already defined in MSVCRTD.lib(MSVCR80D.dll) 1>LIBCMT.lib(tidtable.obj) : error LNK2005: __decode_pointer already defined in MSVCRTD.lib(MSVCR80D.dll) 1>LIBCMT.lib(tolower.obj) : error LNK2005: _tolower already defined in MSVCRTD.lib(MSVCR80D.dll) 1>LIBCMT.lib(crt0dat.obj) : error LNK2005: __amsg_exit already defined in MSVCRTD.lib(MSVCR80D.dll) 1>LIBCMT.lib(crt0dat.obj) : error LNK2005: __initterm_e already defined in MSVCRTD.lib(MSVCR80D.dll) 1>LIBCMT.lib(crt0dat.obj) : error LNK2005: _exit already defined in MSVCRTD.lib(MSVCR80D.dll) 1>LIBCMT.lib(crt0dat.obj) : error LNK2005: __exit already defined in MSVCRTD.lib(MSVCR80D.dll) 1>LIBCMT.lib(crt0dat.obj) : error LNK2005: __cexit already defined in MSVCRTD.lib(MSVCR80D.dll) 1>LIBCMT.lib(lconv.obj) : error LNK2005: _localeconv already defined in MSVCRTD.lib(MSVCR80D.dll) 1>LIBCMT.lib(mlock.obj) : error LNK2005: __unlock already defined in MSVCRTD.lib(MSVCR80D.dll) 1>LIBCMT.lib(mlock.obj) : error LNK2005: __lock already defined in MSVCRTD.lib(MSVCR80D.dll) 1>LIBCMT.lib(winxfltr.obj) : error LNK2005: __XcptFilter already defined in MSVCRTD.lib(MSVCR80D.dll) 1>LIBCMT.lib(crt0init.obj) : error LNK2005: ___xi_a already defined in MSVCRTD.lib(cinitexe.obj) 1>LIBCMT.lib(crt0init.obj) : error LNK2005: ___xi_z already defined in MSVCRTD.lib(cinitexe.obj) 1>LIBCMT.lib(crt0init.obj) : error LNK2005: ___xc_a already defined in MSVCRTD.lib(cinitexe.obj) 1>LIBCMT.lib(crt0init.obj) : error LNK2005: ___xc_z already defined in MSVCRTD.lib(cinitexe.obj) 1>LIBCMT.lib(hooks.obj) : error LNK2005: "void __cdecl terminate(void)" (?terminate@@YAXXZ) already defined in MSVCRTD.lib(MSVCR80D.dll) 1>LIBCMT.lib(crt0.obj) : error LNK2005: _mainCRTStartup already defined in MSVCRTD.lib(crtexe.obj) 1>LIBCMT.lib(errmode.obj) : error LNK2005: ___set_app_type already defined in MSVCRTD.lib(MSVCR80D.dll) 1>LIBCMT.lib(_ctype.obj) : error LNK2005: _isprint already defined in MSVCRTD.lib(MSVCR80D.dll) 1>MSVCRTD.lib(MSVCR80D.dll) : error LNK2005: __stricmp already defined in LIBCMT.lib(stricmp.obj) 1>LINK : warning LNK4098: defaultlib 'MSVCRTD' conflicts with use of other libs; use /NODEFAULTLIB:library 1>LINK : warning LNK4098: defaultlib 'LIBCMT' conflicts with use of other libs; use /NODEFAULTLIB:library 1>D:/home/doc/Visual Studio 2005/Projects/tst_antlr_3/Debug/tst_antlr_3.exe : fatal error LNK1169: one or more multiply defined symbols found |
分析一下错误来源,会发现:
1. 错误来源主要是重复定义的问题,而且重复定义的基本上都是VC Runtime和Standard C++ Library中的函数
2. LIBCMT和LIBCPMT为Release下的Lib,本来不应该出现在Debug版本的链接的Lib中
3. 重复定义的问题主要出现在:LIBCMT, LIBCPMT, MSVCPRTD, MSVCRTD
来看看出问题的LIB是那些:
1. LIBCMT:C Runtime库的多线程静态链接的Release版本
2. LIBCPMT:C++ Standard Library的多线程静态链接的Release版本
3. MSVCPRTD:C++ Standard Library的多线程DLL的Debug版本
4. MSVCRTD:C Runtime Library的多线程DLL的Debug版本
当前我们的配置是多线程DLL的Debug版,因此3和4是应该出现在link的列表中的,不属于多余。而后两者则是只是当多线程静态链接Release版中才会出现。这提示我在项目中加入的ANTLR.LIB可能是造成这个问题的根源,因为静态库的编译选项很容易和主程序发生冲突,并且根据实际信息我们可以看出ANTLR.LIB应该是用多线程静态链接的Release版本来编译的。
这样,解决方法就很清楚了:
1. 切换到Release,因为ANTLR.LIB是在Release下面编译的
2. 把Run Time库的版本修改成多线程静态链接
做了这两个修改之后编译通过。
还有一种方法是,自己用多线程DLL的Debug版重新编译一次ANTLR,生成一个新的ANTLRD.LIB,再link这个Lib也可以解决这个问题。
1. 知道各个不同的LIB代表的版本信息非常重要,可以帮助快速定位问题
2. 在编程的时候,一定要把所有的项目的编译选项(是静态链接Runtime库还是动态链接Runtime库,Debug/Release)配置成一样的。如果部分LIB/OBJ是由第三方提供(OBJ情况很少见),一般情况下只能调整自己的编译选项,除非你可以要求第三方提供其他版本的编译好的LIB
3. 在发布可重用的静态LIB库供其他人调用的时候,最好对应不同的编译选项,乃至VC版本,提供不同版本的LIB。VC自己的Runtime就是最好的例子。