pthread更改全局变量

#include <pthread.h>
#include <iostream>
using namespace std;

int global = 0;

void * assign_value(void *param){
global = 3;
}

int main(){
pthread_t thread;
pthread_create(thread, NULL, assign_value, (void *) nullptr);
pthread_join(thread, NULL);
cout << global << endl;
return 0;
}