Linux gcc 不会编译 SDL C 程序（对 SDL 函数的未定义引用）
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gcc won't compile SDL C Program (undefined reference to SDL functions)
提问by rullof
I recently moved to linux and i'm having an issue with compiling SDL C programs using gcc.
我最近搬到了 linux，我在使用 gcc 编译 SDL C 程序时遇到了问题。
The command i'm using:
我正在使用的命令：
gcc `sdl-config --cflags --libs` -o main main.c
Even by seperating sdl-config flags:
即使通过分离 sdl-config 标志：
gcc `sdl-config --cflags` -c main.c
gcc `sdl-config --libs` -o main main.o
I'm getting the same error:
我收到同样的错误：
/tmp/ccHYyjKd.o: In function `main':
main.c:(.text+0xe): undefined reference to `SDL_SetMainReady'
main.c:(.text+0x18): undefined reference to `SDL_Init'
main.c:(.text+0x31): undefined reference to `SDL_SetVideoMode'
main.c:(.text+0x54): undefined reference to `SDL_MapRGB'
main.c:(.text+0x6b): undefined reference to `SDL_FillRect'
main.c:(.text+0x77): undefined reference to `SDL_Flip'
main.c:(.text+0x83): undefined reference to `SDL_WaitEvent'
main.c:(.text+0x90): undefined reference to `SDL_Quit'
collect2: error: ld returned 1 exit status
My very simple program:
我非常简单的程序：
#include <stdio.h>
#include <stdlib.h>
#define SDL_MAIN_HANDLED
#include <SDL/SDL.h>
int main()
{
// SDL Initialize
SDL_SetMainReady();
SDL_Init(SDL_INIT_VIDEO);
// Screen Initialize
SDL_Surface *screen = SDL_SetVideoMode(640, 480, 32, SDL_SWSURFACE);
Uint32 screenColor = SDL_MapRGB(screen->format, 255, 255, 255);
SDL_FillRect(screen, NULL, screenColor);
SDL_Flip(screen);
// Main Program Loop
SDL_Event event;
do
{
SDL_WaitEvent(&event);
} while (event.type != SDL_QUIT);
// SDL Quit
SDL_Quit();
return 0;
}
采纳答案by Basile Starynkevitch
Order of arguments to gccmatters a lot. Replace
参数的顺序gcc很重要。代替
gcc `sdl-config --libs` -o main main.o
with
和
gcc main.o `sdl-config --libs` -o main
Better yet, learn how to use GNU makeand use a Makefileinspired by this answer...
更好的是，学习如何使用GNU make并使用Makefile受此答案启发的...
Also, always pass -Wall -gto gccuntil your program is bug-free (then use -Wall -O2)
此外，始终传递-Wall -g到gcc直到您的程序没有错误（然后使用-Wall -O2）
回答by sujin
Add -lSDLwith gcc compile command. This will add sdl library. Install sdl developement package before compiling.
-lSDL使用 gcc 编译命令添加。这将添加 sdl 库。编译前安装sdl开发包。
EDIT:
编辑：
gcc -o out main.c -lSDL
or
或者
gcc -I/usr/include/SDL/ main.c -o out -L/usr/lib -lSDL
回答by Alvaro Denis Acosta
I See this from /usr/include/SDL2/SDL_main.h
我从 /usr/include/SDL2/SDL_main.h 看到这个
/* * This is called by the real SDL main function to let the rest of the * library know that initialization was done properly. * * Calling this yourself without knowing what you're doing can cause * crashes and hard to diagnose problems with your application. */ extern DECLSPEC void SDL_SetMainReady(void);
/* * 这由真正的 SDL 主函数调用，让 * 库的其余部分知道初始化已正确完成。* * 在不知道你在做什么的情况下自己调用它会导致 * 崩溃和难以诊断应用程序的问题。*/ extern DECLSPEC void SDL_SetMainReady(void);
Also check this: nm /usr/lib/i386-linux-gnu/libSDL.a | grep SDL_SetMainReady
还要检查这个： nm /usr/lib/i386-linux-gnu/libSDL.a | grep SDL_SetMainReady
This is not the solution but will allow you to focus on the real problem, I think it is not the compilation process.
这不是解决方案，但可以让您专注于真正的问题，我认为这不是编译过程。
回答by ericb
Thanks a lot for the advices ! This helped me to solve an old mystery about SDL symbols never found under Linux :-) As wroten in the comments, the order of gcc line is essential. The makefile was not well written and this was causing the breakage you mentionned.
非常感谢您的建议！这帮助我解决了一个关于在 Linux 下从未发现的 SDL 符号的古老谜团 :-) 正如评论中所写，gcc 行的顺序是必不可少的。生成文件写得不好，这导致了您提到的损坏。
As summary, use : gcc ( flags ) -o name ( include et linking options)
作为总结，使用： gcc ( flags ) -o name ( 包括 et 链接选项)
Last but not least, under x86_64, use gdb64, instead of gdb ( was the next headhache ;-)
最后但并非最不重要的是，在 x86_64 下，使用 gdb64，而不是 gdb（是下一个头痛；-)
As example, a little Makefile I wrote myself (ok, not that good, but works)
例如，我自己写的一个小 Makefile（好吧，不是很好，但有效）
# Makefile pour le contr?le du robot Arduino
# Controle Robot
# Sauf mention contraire, tout est place sous Licence GPL V2
# Historique :
# Etienne HAMON / création du makefile initial (d'après cours IFT1), Novembre 2014
#
# Corrections du Makefile : Eric Bachard décembre 2014
CC = gcc
C_STANDARD = -std=c99
INCLUDE_DIR = inc -I/usr/include/SDL
SOURCES_DIR = sources
BUILD_DIR = build
APPLICATION_NAME = Controle
FILENAME = ${BUILD_DIR}/${APPLICATION_NAME}
CFLAGS = -Wall -ansi ${C_STANDARD}
LDFLAGS = -lSDL $(sdl-config --static-libs) -lm
DEBUG_SUFFIX = _debug
CFLAGS_DEBUG = -v -gdwarf-2 -DDEBUG
OBJS = ${SOURCES_DIR}/*.c
all : ${FILENAME} ${FILENAME}${DEBUG_SUFFIX}
${FILENAME}: ${OBJS}
${CC} ${CFLAGS} -o $@ $^ -I${INCLUDE_DIR} ${LDFLAGS}
${FILENAME}${DEBUG_SUFFIX}: ${OBJS}
${CC} ${CFLAGS} ${CFLAGS_DEBUG} -o $@ $^ -I${INCLUDE_DIR} ${LDFLAGS}
clean:
${RM} *.o ${FILENAME} ${FILENAME}${DEBUG_SUFFIX}
${RM} -rf ${BUILD_DIR}/*.dSYM
回答by awful_answers999
None of the "popular" answers for this question are correct or working. Some of them have nothing to even do with the question being asked. I have the same problem.
这个问题的“流行”答案都不是正确的或有效的。其中一些甚至与提出的问题无关。我也有同样的问题。
SDL docs give an example for compiling like this: gcc -o main main.c `sdl2-config --cflags --libs`
SDL 文档给出了这样编译的示例： gcc -o main main.c `sdl2-config --cflags --libs`
Yet user is suggesting that it is order of arguments causing the problem!! It is not! In fact, their suggested order is something I have never seen before and is certainly not any kind of standard. SDL answers on this site are very low quality!
然而，用户建议这是导致问题的参数顺序！！它不是！事实上，他们建议的顺序是我以前从未见过的，当然不是任何一种标准。此站点上的 SDL 答案质量非常低！
Update: I found a solution for some missing functions. SDL_SetVideoMode does not exist in SDL2. Use SDL_CreateWindow.
更新：我找到了一些缺失功能的解决方案。SDL2 中不存在 SDL_SetVideoMode。使用 SDL_CreateWindow。
