c++ - g++ Windows 链接器 "Undefined reference to..."与 SDL2

Question

概览

我正在尝试将 C++ 项目从 Visual Studio 解决方案转换为 makefile 项目(使用 g++)，作为轻松支持多个平台的第一步。该项目需要 Simple DirectMedia Layer 2 (SDL2) 和 SDL_image 库。该项目之前编译没有错误，我已经纠正了所有停止 g++ 编译器的错误。此时我仍在使用 Windows x64 和 MinGW x64。

问题

在链接时，g++ 抛出错误，好像SDL2 库有问题，声称无法找到SDL2 的所有函数。但是，我知道它正在查找库，因为当我提供不正确的名称或路径时，我会收到一个明确的错误。

这是我的新 makefile，如果不符合标准，我们深表歉意:

# Source files
SRC_ENTITIES = Entity_Block.cpp Entity_Controller.cpp Entity_Cursor.cpp Entity_GreenEye.cpp Entity_Harry.cpp
SRC_ENGINE   = Game.cpp Sound.cpp SoundManager.cpp Sprite.cpp Texture.cpp TextureManager.cpp Entity.cpp EntityManager.cpp
SRC_ENTRY    = main.cpp

# Source and destination
SOURCE    = $(SRC_ENTITIES) $(SRC_ENGINE) $(SRC_ENTRY)
DEST      = crystal_engine.bin

# Compiler options
OUTPUT    = -o $(DEST)
INCLUDES  = -I . -I.\include\windows\SDL2-devel-2.0.4-mingw\SDL2-2.0.4\x86_64-w64-mingw32\include\SDL2 -I.\include\windows\SDL2_image-devel-2.0.1-mingw\SDL2_image-2.0.1\x86_64-w64-mingw32\include\SDL2
LIBPATHS  = -L.\include\windows\SDL2-devel-2.0.4-mingw\SDL2-2.0.4\x86_64-w64-mingw32\lib -L.\include\windows\SDL2_image-devel-2.0.1-mingw\SDL2_image-2.0.1\x86_64-w64-mingw32\lib
LIBRARIES = -lSDL2 -lSDL2main -lSDL2_image
STANDARD  = -std=c++0x
FLAGS     = -Wall

default:
    echo No task selected

compile:
    g++ $(STANDARD) $(INCLUDES) $(FLAGS) $(SOURCE) $(OUTPUT) $(LIBPATHS) $(LIBRARIES)

run:
    ./$(DEST)

run_win:
    $(DEST)

因此命令行当前看起来像这样:

g++ -std=c++0x -I . -I.\include\windows\SDL2-devel-2.0.4-mingw\SDL2-2.0.4\x86_64-w64-mingw32\include\SDL2 -I.\include\windows\SDL2_image-devel-2.0.1-mingw\SDL2_image-2.0.1\x86_64-w64-mingw32\include\SDL2 -Wall Entity_Block.cpp Entity_Controller.cpp Entity_Cursor.cpp Entity_GreenEye.cpp Entity_Harry.cpp Game.cpp Sound.cpp SoundManager.cpp Sprite.cpp Texture.cpp TextureManager.cpp Entity.cpp EntityManager.cpp main.cpp -o crystal_engine.bin -L.\include\windows\SDL2-devel-2.0.4-mingw\SDL2-2.0.4\x86_64-w64-mingw32\lib -L.\include\windows\SDL2_image-devel-2.0.1-mingw\SDL2_image-2.0.1\x86_64-w64-mingw32\lib -lSDL2 -lSDL2main -lSDL2_image

忽略警告(删除 -Wall)，编译的输出如下所示:

C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x169): undefined reference to `SDL_GetTicks'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x2b4): undefined reference to `SDL_GetMouseState'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x2c2): undefined reference to `SDL_PollEvent'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x2d0): undefined reference to `SDL_GetTicks'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x363): undefined reference to `SDL_GetTicks'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x3ef): undefined reference to `SDL_GetTicks'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x46c): undefined reference to `SDL_GetTicks'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x4e3): undefined reference to `SDL_RenderClear'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x4fd): undefined reference to `SDL_RenderPresent'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x597): undefined reference to `SDL_ShowCursor'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x5b1): undefined reference to `SDL_Init'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x633): undefined reference to `SDL_CreateRenderer'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x663): undefined reference to `SDL_CreateWindowAndRenderer'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x678): undefined reference to `SDL_SetWindowTitle'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x836): undefined reference to `SDL_SetRenderDrawColor'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x844): undefined reference to `SDL_RenderClear'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x852): undefined reference to `SDL_RenderPresent'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x865): undefined reference to `SDL_SetHint'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x881): undefined reference to `SDL_RenderSetLogicalSize'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x895): undefined reference to `SDL_GL_SetAttribute'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x8a3): undefined reference to `SDL_GetError'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x8d8): undefined reference to `SDL_GL_SetAttribute'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x8e6): undefined reference to `SDL_GetError'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0xa3d): undefined reference to `SDL_Quit'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0xaba): undefined reference to `SDL_DestroyWindow'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0xad1): undefined reference to `SDL_DestroyRenderer'
f:/mingw/mingw-4.8.1/bin/../lib/gcc/mingw32/4.8.1/../../../../mingw32/bin/ld.exe: C:\Users\[...]\ccSkHjgE.o: bad reloc address 0x1b in section `.text$printf[_printf]'
collect2.exe: error: ld returned 1 exit status
make: *** [compile] Error 1

疑难解答

我尝试了很多方法，从提供库的准确路径到将 SDL 从 2.0.3 更新到 2.0.4。行为是一样的。每个架构的 MinGW devel 文件夹中有两个 include/lib 文件夹，更改我包含的文件夹没有什么不同。

鉴于以下三篇文章，似乎对向 g++ 提供参数的顺序有很多争论:

SDL2 Undefined references to functions

Try to change the sequence of the input params:

I've stumbled over this before (on Linux)

https://askubuntu.com/questions/68922/cant-compile-program-that-uses-sdl-after-upgrade-to-11-10-undefined-reference

Ok, solved. Apparently, for some mysterious reason, the order of the gcc options now matters.

http://smf.cataclysmdda.com/index.php?topic=11028.0

It looks like the SDL2_image library is included, but the main SDL2 library is not (the references could be out of order).

不幸的是，无论我如何重新排列参数，我似乎都无法改变这个结果。与大多数问题不同，我什至无法让它变得更糟!非常感谢任何帮助。

我认为这与我的代码没有任何关系，考虑到没有链接 -c 的编译可以很好地完成，但如果它有助于解决问题，我会非常乐意发布一些它的(它是很多代码)。

编辑

根据请求，这里是使用 -v 和 -Wall 选项进行完整编译的转储。它对于这个问题来说太大了，所以我把它扔进了一个 pastebin。

http://pastebin.com/ydET621i

当使用 -DDECLSPEC=__declspec(dllimport) 选项时，输出变为:

C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x169): undefined reference to `_imp__SDL_GetTicks'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x2b6): undefined reference to `_imp__SDL_GetMouseState'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x2c6): undefined reference to `_imp__SDL_PollEvent'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x2d6): undefined reference to `_imp__SDL_GetTicks'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x36b): undefined reference to `_imp__SDL_GetTicks'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x3f9): undefined reference to `_imp__SDL_GetTicks'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x478): undefined reference to `_imp__SDL_GetTicks'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x4f1): undefined reference to `_imp__SDL_RenderClear'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x50d): undefined reference to `_imp__SDL_RenderPresent'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x5a9): undefined reference to `_imp__SDL_ShowCursor'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x5c5): undefined reference to `_imp__SDL_Init'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x649): undefined reference to `_imp__SDL_CreateRenderer'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x67b): undefined reference to `_imp__SDL_CreateWindowAndRenderer'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x692): undefined reference to `_imp__SDL_SetWindowTitle'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x852): undefined reference to `_imp__SDL_SetRenderDrawColor'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x862): undefined reference to `_imp__SDL_RenderClear'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x872): undefined reference to `_imp__SDL_RenderPresent'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x887): undefined reference to `_imp__SDL_SetHint'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x8a5): undefined reference to `_imp__SDL_RenderSetLogicalSize'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x8bb): undefined reference to `_imp__SDL_GL_SetAttribute'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x8cb): undefined reference to `_imp__SDL_GetError'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x902): undefined reference to `_imp__SDL_GL_SetAttribute'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x912): undefined reference to `_imp__SDL_GetError'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0xa6b): undefined reference to `_imp__SDL_Quit'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0xaea): undefined reference to `_imp__SDL_DestroyWindow'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0xb03): undefined reference to `_imp__SDL_DestroyRenderer'
f:/mingw/mingw-4.8.1/bin/../lib/gcc/mingw32/4.8.1/../../../../mingw32/bin/ld.exe: C:\Users\[...]\ccZ61vi9.o: bad reloc address 0x1b in section `.text$printf[_printf]'
collect2.exe: error: ld returned 1 exit status
make: *** [compile] Error 1

运行 ar -t libSDL2.a 产生以下结果:

SDL.o
SDL_assert.o
SDL_error.o
SDL_hints.o
SDL_log.o
SDL_atomic.o
SDL_spinlock.o
SDL_audio.o
SDL_audiocvt.o
SDL_audiodev.o
SDL_audiotypecvt.o
SDL_mixer.o
SDL_wave.o
SDL_cpuinfo.o
SDL_dynapi.o
SDL_clipboardevents.o
SDL_dropevents.o
SDL_events.o
SDL_gesture.o
SDL_keyboard.o
SDL_mouse.o
SDL_quit.o
SDL_touch.o
SDL_windowevents.o
SDL_rwops.o
SDL_haptic.o
SDL_gamecontroller.o
SDL_joystick.o
e_atan2.o
e_log.o
e_pow.o
e_rem_pio2.o
e_sqrt.o
k_cos.o
k_rem_pio2.o
k_sin.o
k_tan.o
s_atan.o
s_copysign.o
s_cos.o
s_fabs.o
s_floor.o
s_scalbn.o
s_sin.o
s_tan.o
SDL_power.o
SDL_d3dmath.o
SDL_render.o
SDL_yuv_mmx.o
SDL_yuv_sw.o
SDL_render_d3d.o
SDL_render_d3d11.o
SDL_render_gl.o
SDL_shaders_gl.o
SDL_render_gles.o
SDL_render_gles2.o
SDL_shaders_gles2.o
SDL_render_psp.o
SDL_blendfillrect.o
SDL_blendline.o
SDL_blendpoint.o
SDL_drawline.o
SDL_drawpoint.o
SDL_render_sw.o
SDL_rotate.o
SDL_getenv.o
SDL_iconv.o
SDL_malloc.o
SDL_qsort.o
SDL_stdlib.o
SDL_string.o
SDL_thread.o
SDL_timer.o
SDL_RLEaccel.o
SDL_blit.o
SDL_blit_0.o
SDL_blit_1.o
SDL_blit_A.o
SDL_blit_N.o
SDL_blit_auto.o
SDL_blit_copy.o
SDL_blit_slow.o
SDL_bmp.o
SDL_clipboard.o
SDL_egl.o
SDL_fillrect.o
SDL_pixels.o
SDL_rect.o
SDL_shape.o
SDL_stretch.o
SDL_surface.o
SDL_video.o
SDL_nullevents.o
SDL_nullframebuffer.o
SDL_nullvideo.o
SDL_diskaudio.o
SDL_dummyaudio.o
SDL_windows.o
SDL_xinput.o
SDL_windowsclipboard.o
SDL_windowsevents.o
SDL_windowsframebuffer.o
SDL_windowskeyboard.o
SDL_windowsmessagebox.o
SDL_windowsmodes.o
SDL_windowsmouse.o
SDL_windowsopengl.o
SDL_windowsopengles.o
SDL_windowsshape.o
SDL_windowsvideo.o
SDL_windowswindow.o
SDL_winmm.o
SDL_directsound.o
SDL_xaudio2.o
SDL_dinputjoystick.o
SDL_mmjoystick.o
SDL_windowsjoystick.o
SDL_xinputjoystick.o
SDL_dinputhaptic.o
SDL_windowshaptic.o
SDL_xinputhaptic.o
SDL_syspower.o
SDL_sysfilesystem.o
SDL_sysmutex.o
SDL_syssem.o
SDL_systhread.o
SDL_systls.o
SDL_syscond.o
SDL_systimer.o
SDL_sysloadso.o

Answer 1

感谢@J.JHakala 和@user657267 的建议，我得出的结论是我安装的 MinGW 实际上是 32 位的!鉴于我使用的是 64 位库，它们会像任何其他库一样读入，但无法识别其中的函数。

对于遇到此问题的任何其他人，您可以下载 64 位版本的 MinGW 或者切换您要导入的库。

x86: i686-w64-mingw32

x64: x86_64-w64-mingw32