pthread_create 報函數參數不匹配問題

pthread_create方法遇到類方法時總會報  argument of type ‘void* (Thread::)(void*)’ does not match ‘void* (*)(void*)’
pthread_create方法第三個參數只能是C函數指針或者類到靜態函數指針。
下面記錄一下解決方法

 

include <stdio.h>
#include <pthread.h>
#include <unistd.h>

class Thread{
public:
    Thread(int num = 5):_num(num){ }

    static void *work(void *args){  //靜態函數有訪問函數, 變量限制, 這里直接傳入類指針變量
        Thread *handle = (Thread*)args;
        for (int i = 0; i < handle->_num; ++i){
            printf("sleep i = %d\n", i); 
            sleep(1);
        }   
        pthread_exit(NULL);
    }   

    int _num;
};

void *inc_count(void *args){
    for (int i = 0; i < 5; ++i){
        printf("inc_count i = %d\n", i); 
        sleep(1);
    }   
    pthread_exit(NULL);
}

int main(){
    Thread obj; 
    pthread_t threads[2];

    pthread_create(&threads[0], NULL, inc_count, NULL);     //必須是C函數指針
    pthread_create(&threads[1], NULL, Thread::work, &obj);  //或者時類靜態函數指針
    obj._num = 10; 
    
    pthread_join(threads[0], NULL);
    pthread_join(threads[1], NULL);
    return 0;
}