【发布时间】:2015-10-06 17:45:07
【问题描述】:
以下来自教程网站的基本 SDL2 代码引起了一些奇怪的问题:
#include <SDL2/SDL.h>
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#define SCREENH 768
#define SCREENW 1366
SDL_Window *window = NULL;
SDL_Surface *screenSurface = NULL;
SDL_Surface *windowSurface = NULL;
int init_SDL() {
int success = 0;
if(SDL_Init(SDL_INIT_VIDEO) < 0) {
printf("SDL could not initialize! ");
printf("SDL_Error: %s\n",SDL_GetError());
success = -1;
}
else {
window = SDL_CreateWindow("SDL2_Tutorial02",SDL_WINDOWPOS_UNDEFINED,SDL_WINDOWPOS_UNDEFINED,SCREENW,SCREENH,SDL_WINDOW_SHOWN);
if(window == NULL) {
printf("Window could not be created! ");
printf("SDL Error: %s\n",SDL_GetError());
}
else {
screenSurface = SDL_GetWindowSurface(window);
}
}
return success;
}
int loadMedia() {
int success = 0;
windowSurface = SDL_LoadBMP("Images/Hallo.bmp");
if(windowSurface == NULL) {
printf("Unable to load image! ");
printf("SDL Error: %s\n",SDL_GetError());
success = -1;
}
return success;
}
void close() {
SDL_FreeSurface(windowSurface);
windowSurface = NULL;
SDL_DestroyWindow(window);
window = NULL;
SDL_Quit();
}
int main(int argc,char *argv[]) {
assert(init_SDL() == 0);
assert(loadMedia() == 0);
SDL_BlitSurface(windowSurface,NULL,screenSurface,NULL);
SDL_UpdateWindowSurface(window);
SDL_Delay(3000);
close();
exit(EXIT_SUCCESS);
}
只要调用了位于 close() 中的 SDL_Quit(),我就会收到内存访问错误。使用 GDB 揭示了以下内容:
49 SDL_Quit();
(gdb) n
Program received signal SIGBUS, Bus error.
0x00007ffff68a5895 in ?? () from /usr/lib/x86_64-linux-gnu/libX11.so.6
(gdb)
奇怪的是,当我像这样将 SDL_Quit() 放在 close() 之外时:
void close() {
SDL_FreeSurface(windowSurface);
windowSurface = NULL;
SDL_DestroyWindow(window);
window = NULL;
}
int main(int argc,char *argv[]) {
assert(init_SDL() == 0);
assert(loadMedia() == 0);
SDL_BlitSurface(windowSurface,NULL,screenSurface,NULL);
SDL_UpdateWindowSurface(window);
SDL_Delay(3000);
close();
SDL_Quit();
exit(EXIT_SUCCESS);
}
一切都很好。 SDL_Quit() 可以正常工作。为什么我在另一个函数中调用 SDL_Quit() 会导致 SIGBUS 错误?
编辑:此代码是在 ubuntu 14.04 上使用 gcc 和以下编译命令编译的
gcc -g3 -o tutorial tutorial.c `sdl2-config --cflags --libs`
【问题讨论】: