c++ - 未解析的外部符号，即使我认为我链接正确(MSVC)

Question

我有一个使用 SDL 作为外部库的项目。该项目使用了 _SDL_WM_SetCaption、_SDL_FillRect 或 _SDL_MapRGBA 等函数。我告诉链接器包含两个库 SDL.lib 和 SDLmain.lib，并告诉它查看放置这些库的文件夹。我还用 dumpbin.exe 检查了库文件，函数在那里。但是，它仍然无法编译/链接？为什么？有人有什么想法吗？

编辑:这里是链接器/编译器错误的示例输出:

14>libtestd.lib(sdlgl.obj) : error LNK2019: unresolved external symbol _SDL_WM_SetCaption referenced in function "public: void __thiscall SDLGLEngine::SetTitle(char *)" (?SetTitle@SDLGLEngine@@QAEXPAD@Z)
14>libtestd.lib(sdlgl.obj) : error LNK2019: unresolved external symbol _SDL_FillRect referenced in function "public: bool __thiscall SDLGLEngine::Init(int,int,int,bool)" (?Init@SDLGLEngine@@QAE_NHHH_N@Z)
14>libtestd.lib(sdlgl.obj) : error LNK2019: unresolved external symbol _SDL_MapRGBA referenced in function "public: bool __thiscall SDLGLEngine::Init(int,int,int,bool)" (?Init@SDLGLEngine@@QAE_NHHH_N@Z)
14>libtestd.lib(sdlgl.obj) : error LNK2019: unresolved external symbol _SDL_SetVideoMode referenced in function "public: bool __thiscall SDLGLEngine::Init(int,int,int,bool)" (?Init@SDLGLEngine@@QAE_NHHH_N@Z)
14>libtestd.lib(sdlgl.obj) : error LNK2019: unresolved external symbol _SDL_GL_SetAttribute referenced in function "public: bool __thiscall SDLGLEngine::Init(int,int,int,bool)" (?Init@SDLGLEngine@@QAE_NHHH_N@Z)
14>libtestd.lib(sdlgl.obj) : error LNK2019: unresolved external symbol _SDL_Quit referenced in function "public: bool __thiscall SDLGLEngine::Init(int,int,int,bool)" (?Init@SDLGLEngine@@QAE_NHHH_N@Z)
14>libtestd.lib(sdlgl.obj) : error LNK2019: unresolved external symbol _SDL_Init referenced in function "public: bool __thiscall SDLGLEngine::Init(int,int,int,bool)" (?Init@SDLGLEngine@@QAE_NHHH_N@Z)

Answer 1

可能的原因:

• sdl.lib 和 sdlmain.lib 设置未添加到依赖列表
• 它们的位置没有添加到链接器查找的目录列表中
• 您的库的 32 位和 64 位版本不匹配。