Question

我正在尝试使用C ++和SDL创建一个简单的多线程示例，如下所示：

#include <iostream>
#include "SDL/SDL_image.h"
#include "SDL/SDL.h"
#include "SDL/SDL_thread.h"
#include "X11/Xlib.h"
#include "SDLAbstractionLayer.h"
#include <string>

using namespace std;

SDL_Thread* thread = NULL;
bool quit = false;

int myThread(void* data) {
   while (!quit) {
      //caption animation
      SDL_WM_SetCaption ("Thread is running", NULL);
      SDL_Delay(250);

      SDL_WM_SetCaption("Thread is running.", NULL);
      SDL_Delay(250);

      SDL_WM_SetCaption("Thread is running..", NULL);
      SDL_Delay(250);

      SDL_WM_SetCaption("Thread is running...", NULL);
      SDL_Delay(250);
   }

   return 0;
}

int main(int argc, char* argv[]) {
   SDL_Surface* screen = init(640, 480, "");
   XInitThreads();

   Surface test("resources/image.png");
   thread = SDL_CreateThread(myThread, NULL);
   SDL_Event event;

   while (!quit) {
      if(SDL_PollEvent(&event)) {
         if (event.type == SDL_QUIT) {
            quit = true;
            break;
         }

         fillScreen(screen, Surface::WHITE);
         applySurface(0, 0, test, screen);
         flip(screen);
      }
   }

   cleanUp();
   SDL_KillThread(thread);

   return 0;
}

问题在于，当我在Eclipse或终端中运行它时，我收到此消息：

XIO:  fatal IO error 0 (Success) on X server ":0.0"
  after 113 requests (113 known processed) with 0 events remaining.

或者这个：

XIO:  fatal IO error 11 (Resource temporarily unavailable) on X server ":0.0"
  after 113 requests (113 known processed) with 2 events remaining.

我正在使用带有Eclipse Kepler的Ubuntu 13。我试过做一些研究，但是找不到任何有用的东西。

编辑：所以我更新了代码以包含一个计数器和几个cout的所有地方：

int myThread(void* data) {
   while (!quit) {
      //caption animation
      SDL_WM_SetCaption ("Thread is running", NULL);
      SDL_Delay(250);

      cout << "Thread is running 1" << endl;

      SDL_WM_SetCaption("Thread is running.", NULL);
      SDL_Delay(250);

      cout << "Thread is running 2" << endl;

      SDL_WM_SetCaption("Thread is running..", NULL);
      SDL_Delay(250);

      cout << "Thread is running 3" << endl;

      SDL_WM_SetCaption("Thread is running...", NULL);
      SDL_Delay(250);

      cout << "Thread is running 4" << endl;
   }

   return 0;
}

int main(int argc, char* argv[]) {
   SDL_Surface* screen = init(640, 480, "");
   XInitThreads();

   Surface test("resources/image.png");
   thread = SDL_CreateThread(myThread, NULL);
   SDL_Event event;
   int count = 1;

   while (!quit) {
      if(SDL_PollEvent(&event)) {
         if (event.type == SDL_QUIT) {
            quit = true;
            break;
         }

         fillScreen(screen, Surface::WHITE);
         applySurface(0, 0, test, screen);
         flip(screen);

         cout << "finished iteration " << count++ << endl;
      }
   }

这是运行一次后控制台的输出：

finished iteration 1
Thread is running 1
XIO:  fatal IO error 0 (Success) on X server ":0.0"
      after 113 requests (113 known processed) with 0 events remaining.

然后，在第二次运行之后：

finished iteration 1
finished iteration 2
Thread is running 1
Thread is running 2
XIO:  fatal IO error 0 (Success) on X server ":0.0"
      after 116 requests (116 known processed) with 0 events remaining.

Answer 1

如有疑问，请在主线程上执行所有SDL操作。

主要例外是SDL_PostEvent()。

Answer 2

啊没关系。我收到了一封电子邮件的回复，我发送给制作我正在关注的教程的人：

是的，我正在修复SDL 2.0教程的应用程序中的错误。查看SDL 2.0多线程示例以获取修复。问题是SDL有多线程做渲染不起作用。所以从另一个线程设置标题不行。在2.0教程中，渲染是在一个线程和控制台输出中在另一个。

SDL和X11多线程致命IO错误

2 个答案: