Linux 多线程：深入互斥与同步机制

1. 互斥

1.1 为什么需要互斥

多线程抢票模型演示了并发访问共享数据的问题。

#include<iostream>
#include<unistd.h>
#include<pthread.h>
#include<string>
#include<vector>
using namespace std;
#define NUM 4
int ticket = 100; // 用多线程，模拟一轮抢票

class ThreadData {
public:
    ThreadData(int number){ _thread_name = "thread-" + to_string(number); }
public:
    string _thread_name;
};

void* GetTicket(void* args) {
    ThreadData* td = static_cast<ThreadData*>(args);
    const char* name = td->_thread_name.c_str();
    while(true) {
        if(ticket > 0){
            usleep(5000);
            printf("i am %s, get a ticket:%d\n", name, ticket);
            ticket--;
        } else break;
    }
    (, name);
     ;
}

{
    vector<> tids;
    vector<ThreadData*> thread_datas;
    ( i=; i<NUM; i++) {
         tid;
        ThreadData* td =  (i);
        thread_datas.(td);
        (&tid, , GetTicket, thread_datas[i]);
        tids.(tid);
    }
    ( &e : tids) {
        (e, );
    }
    ( &e : thread_datas) {
         e;
    }
     ;
}