在线程创建时将一个简单的整数传递给线程的启动函数

Question

代码是示例，我需要做的是修改。

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

void  *my_function (void*); // Function for the thread 

int main ()
{
    pthread_t   my_thread ; // Declare a thread identifier
    int  rc1, x = 7; 

    // Create my_thread 
    if ( (rc1 = pthread_create (& my_thread, NULL,  & my_function,  (void*) &x)))
    {
        printf ("Error in creating thread %d\n", rc1);
    }

    pthread_join ( my_thread, NULL); // wait for thread to exit

    return (0); // exit the main function
}


// The my_thread is created with my_function() which accepts an argument 
void  *my_function(void* arg)
{
    int i = *(int*)arg;

    printf ("The argument which this thread received is %d \n", i ) ; 

    pthread_exit (NULL) ;    // thread exits
}

问题是：在线程创建时将一个简单的整数传递给线程的启动函数。但是我不知道如何将一个简单的整数传递给线程的启动函数，也不知道什么是线程创建时间。

Answer 1

如果你的实现有intptr_t（大部分都有），你可以修改代码如下：

int  rc1; 
intptr_t x = 7
...
pthread_create (&my_thread, NULL, &my_function, (void*)x));
...
void* my_function(void* arg)
{
    intptr_t i = (intptr_t)arg;
...