尝试创建posix线程并从'void *'到'void *（__ attribute __（（__ cdecl__））*）（void *）错误进行无效转换

Question

对不起，如果我不像我应该那样描述，我几乎睡着了。我试图在我的c ++代码中用m ++编译g ++来创建一个posix线程。这是我正在尝试编译的代码的除外

static void processNextNodeOnQueue(queue<TreeNode*> &toComputeQueue) {...}

void static processNodes(void* ptr) {
    pair<queue<TreeNode*>*, bool*> *input = (pair<queue<TreeNode*>*, bool*>*) ptr;
    while(*(input->second)) {
        pthread_mutex_lock(&mutex1);
        if(input->first->empty()) return;
        pthread_mutex_unlock(&mutex1);
        processNextNodeOnQueue(*(input->first));
    }   
}

void startThinking() {
    thinking = true;
    mutex1 = PTHREAD_MUTEX_INITIALIZER;
    pthread_t thread;
    pair<queue<TreeNode*>*, bool*> *input = new pair<queue<TreeNode*>*, bool*>(&toComputeQueue, &thinking);
    int thereadId = pthread_create(&thread, NULL, (void*)&processNodes, (void*) input );
    delete input;
}

void stopThinking() {
    //set thinking to false and wait for threads to wrap up
    thinking = false;
}

void processForTime(double seconds) {
    clock_t t;
    int f;
    t = clock();
    startThinking();
    //something to wait for an amount of time
    stopThinking();
}

如果我错过了什么

，这是完整的编译器输出

C:\Users\Maxwell\SkyDrive\RPI\Fall 2013\IHSS-1964\Connect 4\MaxAI>g++ -g -pthread -std=c++11 -o3 *.cpp -o Max.exe
In file included from unit_tests.h:5:0,
                 from main.cpp:11:
search_tree.h: In member function 'void BoardSearchTree::startThinking()':
search_tree.h:221:85: error: invalid conversion from 'void*' to 'void* (__attribute__((__cdecl__)) *)(void*)' [-fpermissive]
   int thereadId = pthread_create(&thread, NULL, (void*)&processNodes, (void*) input );
                                                                                     ^
In file included from search_tree.h:12:0,
                 from unit_tests.h:5,
                 from main.cpp:11:
c:\mingw\include\pthread.h:940:31: error:   initializing argument 3 of 'int pthread_create(pthread_t*, pthread_attr_t_*const*, void* (__attribute__((__cdecl__)) *)(void*), void*)' [-fpermissive] PTW32_DLLPORT int PTW32_CDECL pthread_create (pthread_t * tid,

Answer 1

pthread_create的第三个参数是void *(*start_routine) (void *) - 一个函数指针。您正在将函数转换为(void*)，这既不必要又不正确。只需删除演员：

pthread_create(&thread, NULL, processNodes, (void*) input );

此外，由于input是一个指针，您不需要将其强制转换，所有指针（保存指向成员的指针）都可以隐式转换为void*）：

pthread_create(&thread, NULL, processNodes, input );

Answer 2

假设您正在使用here中的pthread-w32库，则以下标题信息是相关的：

#define PTW32_CDECL __cdecl

PTW32_DLLPORT int PTW32_CDECL pthread_create (pthread_t * tid,
                            const pthread_attr_t * attr,
                            void *(PTW32_CDECL *start) (void *),
                            void *arg);

这表明start参数应该是使用__cdecl calling convention的函数指针。

尝试将processNodes函数原型更改为以下内容：

static void PTW32_CDECL processNodes(void* ptr)

然后编译器应该使用pthread_create所期望的正确调用约定来创建线程函数。