c++ - 如何修复静态库？

Question

我正在尝试学习如何调试静态库，尤其是我正在尝试修复 JsonCpp。

我可以使用哪些项目设置来准确查看 Visual Studio 输出窗口中链接的内容？

============================================= ===================================

这是我遇到的错误:

Error   1   error LNK2005: "public: __thiscall std::_Lockit::~_Lockit(void)" (??1_Lockit@std@@QAE@XZ) already defined in libcpmtd.lib(xlock.obj)    msvcprtd.lib

Error   2   error LNK2005: "public: __thiscall std::_Lockit::_Lockit(int)" (??0_Lockit@std@@QAE@H@Z) already defined in libcpmtd.lib(xlock.obj) msvcprtd.lib

Error   3   error LNK2005: "void __cdecl std::_Debug_message(wchar_t const *,wchar_t const *,unsigned int)" (?_Debug_message@std@@YAXPB_W0I@Z) already defined in libcpmtd.lib(stdthrow.obj)    msvcprtd.lib

Error   4   error LNK2005: "public: __thiscall std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >::~basic_string<char,struct std::char_traits<char>,class std::allocator<char> >(void)" (??1?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@QAE@XZ) already defined in Core.obj msvcprtd.lib

Error   5   error LNK2005: "public: __thiscall std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >(char const *)" (??0?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@QAE@PBD@Z) already defined in Core.obj   msvcprtd.lib

Error   6   error LNK2005: "public: __thiscall std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &)" (??0?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@QAE@ABV01@@Z) already defined in Core.obj msvcprtd.lib

Error   7   error LNK2005: "public: char const * __thiscall std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >::c_str(void)const " (?c_str@?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@QBEPBDXZ) already defined in Core.obj    msvcprtd.lib

Error   8   error LNK2005: "public: void __thiscall std::_Container_base_secure::_Orphan_all(void)const " (?_Orphan_all@_Container_base_secure@std@@QBEXXZ) already defined in Core.obj msvcprtd.lib

Error   9   error LNK2005: "public: __thiscall std::_Container_base_secure::~_Container_base_secure(void)" (??1_Container_base_secure@std@@QAE@XZ) already defined in Core.obj  msvcprtd.lib

Error   10  error LNK2005: "public: __thiscall std::_Container_base_secure::_Container_base_secure(void)" (??0_Container_base_secure@std@@QAE@XZ) already defined in Core.obj   msvcprtd.lib

Error   11  error LNK2005: "public: class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > & __thiscall std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >::operator=(char const *)" (??4?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@QAEAAV01@PBD@Z) already defined in libcpmtd.lib(locale0.obj)  msvcprtd.lib

Error   12  error LNK2005: "public: __thiscall std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >(unsigned int,char)" (??0?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@QAE@ID@Z) already defined in Serialization.obj  msvcprtd.lib

Error   13  error LNK2005: "public: unsigned int __thiscall std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >::size(void)const " (?size@?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@QBEIXZ) already defined in Core.obj    msvcprtd.lib

Error   14  error LNK2005: "public: void __thiscall std::basic_ios<char,struct std::char_traits<char> >::setstate(int,bool)" (?setstate@?$basic_ios@DU?$char_traits@D@std@@@std@@QAEXH_N@Z) already defined in Serialization.obj    msvcprtd.lib

Error   15  error LNK2005: "public: static bool __cdecl std::char_traits<char>::eq_int_type(int const &,int const &)" (?eq_int_type@?$char_traits@D@std@@SA_NABH0@Z) already defined in Serialization.obj   msvcprtd.lib

Error   16  error LNK2005: "public: static int __cdecl std::char_traits<char>::eof(void)" (?eof@?$char_traits@D@std@@SAHXZ) already defined in Serialization.obj    msvcprtd.lib

Error   17  error LNK2005: "public: static unsigned int __cdecl std::char_traits<char>::length(char const *)" (?length@?$char_traits@D@std@@SAIPBD@Z) already defined in Core.obj   msvcprtd.lib

Error   18  error LNK2005: _malloc already defined in LIBCMTD.lib(dbgmalloc.obj)    MSVCRTD.lib

Error   19  error LNK2005: _free already defined in LIBCMTD.lib(dbgfree.obj)    MSVCRTD.lib

Error   20  error LNK2005: "public: virtual __thiscall std::exception::~exception(void)" (??1exception@std@@UAE@XZ) already defined in LIBCMTD.lib(stdexcpt.obj)    MSVCRTD.lib

Error   21  error LNK2005: "public: __thiscall std::exception::exception(void)" (??0exception@std@@QAE@XZ) already defined in LIBCMTD.lib(stdexcpt.obj) MSVCRTD.lib

Error   22  error LNK2005: "public: __thiscall std::exception::exception(class std::exception const &)" (??0exception@std@@QAE@ABV01@@Z) already defined in LIBCMTD.lib(stdexcpt.obj)   MSVCRTD.lib

Error   23  error LNK2005: _strchr already defined in LIBCMTD.lib(strchr.obj)   MSVCRTD.lib

Error   24  error LNK2005: __invalid_parameter already defined in LIBCMTD.lib(invarg.obj)   MSVCRTD.lib

Error   25  error LNK2005: __CrtDbgReportW already defined in LIBCMTD.lib(dbgrptw.obj)  
MSVCRTD.lib

Error   26  error LNK2005: "public: __thiscall std::exception::exception(char const * const &)" (??0exception@std@@QAE@ABQBD@Z) already defined in LIBCMTD.lib(stdexcpt.obj)    MSVCRTD.lib

Error   27  error LNK2005: _memmove_s already defined in LIBCMTD.lib(memmove_s.obj) MSVCRTD.lib

Error   28  error LNK2005: _sprintf already defined in LIBCMTD.lib(sprintf.obj) MSVCRTD.lib

Error   29  error LNK2005: _sprintf_s already defined in LIBCMTD.lib(sprintf.obj)   MSVCRTD.lib

Error   30  error LNK2005: _strpbrk already defined in LIBCMTD.lib(strpbrk.obj) MSVCRTD.lib

Error   31  error LNK2005: "private: __thiscall type_info::type_info(class type_info const &)" (??0type_info@@AAE@ABV0@@Z) already defined in LIBCMTD.lib(typinfo.obj)  MSVCRTD.lib

Error   32  error LNK2005: "private: class type_info & __thiscall type_info::operator=(class type_info const &)" (??4type_info@@AAEAAV0@ABV0@@Z) already defined in LIBCMTD.lib(typinfo.obj)    MSVCRTD.lib

Warning 33  warning LNK4098: defaultlib 'MSVCRTD' conflicts with use of other libs; use /NODEFAULTLIB:library   Afterfuture Game Engine

Error   34  fatal error LNK1169: one or more multiply defined symbols found C:\Users\Blake\Desktop\Afterfuture\Afterfuture Game Engine\Debug\Afterfuture Game Engine.exe

Answer 1

问题是您将同一个库的两个不同版本链接在一起。如果库静态链接到标准 C 库的调试、单线程版本，则使用该库的应用程序无法动态链接到同一运行时库的发布、多线程版本。

否则，例如，如果内存从一个分配器分配但又返回给另一个，那么您最终会遇到两个不同的内存分配器和困惑。因此，即使链接器允许您这样做，应用程序也无法安全地与库进行互操作——那有什么意义呢？

假设库已经静态链接到标准 C 库的多线程版本，而应用程序动态链接到单线程版本。如果库在应用程序分配的对象上调用 delete 并且库的分配器必须释放一个对象，尽管从未分配过一个对象，会发生什么情况？!

根本没有办法使这项工作可靠。要么将所有内容静态链接到完全相同的静态库，要么动态链接所有内容。 (这基本上是首选动态链接的原因。否则，您必须同时链接所有 库和应用程序，否则非常要小心。)认为自己很幸运符号发生冲突，您会收到警告。