没有匹配的函数调用'pthread_create' [英] No matching function call to 'pthread_create'

问题描述

我使用Xcode和C ++制作一个简单的游戏。
问题是以下代码：

  #include< pthread.h> 
 
 void * draw（void * pt）{
 // ... 
} 
 
 void * input（void * pt）{
 // ... 
} 
 
 void Game :: create_threads（void）{
 pthread_t draw_t，input_t; 
 pthread_create（& draw_t，NULL，& Game :: draw，NULL）; //错误
 pthread_create（& input_t，NULL，& Game :: draw，NULL）; //错误
 // ... 
} 
  

但Xcode给了我错误：没有匹配的函数调用'pthread_create'。我不知道因为我已经包括 pthread.h 。

出了什么问题？ / p>

谢谢！

解决方案

线程回调必须是一个（void *）（*）（void *）类型的函数。

你仍然可以包含这个函数作为类函数，静态的。

例如：

  class Game {
 protected：
 void draw（void）; 
 static void * game_draw_thread_callback（void *）; 
}; 
 
 //并在您的.cpp文件中... 
 
 void Game :: create_threads（void）{
 //将Game实例作为线程回调用户数据
 pthread_create（&draw_t，NULL，Game :: game_draw_thread_callback，this）; 
} 
 
 static void * Game :: game_draw_thread_callback（void * game_ptr）{
 //我是一个C程序员，对不起C的演员。 
 Game * game =（Game *）game_ptr; 
 
 //运行实际绘图的方法，
 //但是现在，你在一个线程！ 
 game-> draw（）; 
} 
  

I'm using Xcode and C++ to make a simple game. The problem is the following code:

#include <pthread.h>

void *draw(void *pt) {
    // ...
}

void *input(void *pt) {
    // ....
}

void Game::create_threads(void) {
    pthread_t draw_t, input_t;
    pthread_create(&draw_t, NULL, &Game::draw, NULL);   // Error
    pthread_create(&input_t, NULL, &Game::draw, NULL);  // Error
    // ...
}

But Xcode gives me the error: "No matching function call to 'pthread_create'". I haven't an idea 'cause of I've included pthread.h already.

What's wrong?

Thanks!

解决方案

As Ken states, the function passed as the thread callback must be a (void*)(*)(void*) type function.

You can still include this function as a class function, but it must be declared static. You'll need a different one for each thread type (e.g. draw), potentially.

For example:

class Game {
   protected:
   void draw(void);
   static void* game_draw_thread_callback(void*);
};

// and in your .cpp file...

void Game::create_threads(void) {
   //  pass the Game instance as the thread callback's user data
   pthread_create(&draw_t, NULL, Game::game_draw_thread_callback, this);
}

static void* Game::game_draw_thread_callback(void *game_ptr) {
   //  I'm a C programmer, sorry for the C cast.
   Game * game = (Game*)game_ptr;

   //  run the method that does the actual drawing,
   //  but now, you're in a thread!
   game->draw();
}

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