19.线程的创建终止汇合及分离

1.创建新的线程

#include<stdio.h>
#include<pthread.h>
#include<unistd.h>
#include<sys/types.h>

void *doit(void *arg){
    printf("arg: %s\tpid: %d\ttid:%lu\n", (char *)arg, getpid(), pthread_self());
    return NULL;
}

int main(void){
    pthread_t tid;
    //create a new thread;
    pthread_create(&tid, NULL, doit, "New-thread");
    //we have 2 threads now, main and new created thread;
    //the 2 threads running asynchronous
    sleep(1);
    doit("main");

    return 0;
}

编译运行：

zhongjun@Eclipse:~$ gcc pthread.c -lpthread
zhongjun@Eclipse:~$ ./a.out
arg: New-thread pid: 227        tid:140124534671104
arg: main       pid: 227        tid:140124545353536

2.线程的分离

#include<stdio.h>
#include<pthread.h>
#include<unistd.h>
#include<sys/types.h>

void *doit(void *arg){
    for(int i = 0; i < 5; i++){
        printf("arg: %s\tpid: %d\ttid:%lu\n", (char *)arg, getpid(), pthread_self());
        sleep(4);
    }
    return NULL;
}

int main(void){
    pthread_t tid;
    //create a new thread;
    pthread_create(&tid, NULL, doit, "New-thread");
    //detach new thread
    pthread_detach(tid);
    for(int i = 0; i < 5; i++){
        printf("pid: %d\ttid: %lu\n", getpid(), pthread_self());
        sleep(5);
    }

    return 0;
}

编译运行后，通过命令top -H -p "thread_id"查看效果。

3.线程的汇合和终止

#include<stdio.h>
#include<pthread.h>
#include<unistd.h>
#include<sys/types.h>

void *handler(void *arg){
    printf("I am running, handler...\n");
    sleep(5);
    return (void *)1;
}

void *handler_cancel(void *arg){
    printf("Running thread cancel...\n");
    while(1){
        printf("cancel...\n");
        sleep(2);
    }

    return NULL;
}
void *handler_exit(void *arg){
    printf("handler-exit running...\n");
    sleep(5);
    pthread_exit((void *)5);
}
int main(void){
    void *ret;
    pthread_t tid;
    pthread_create(&tid, NULL, handler, NULL);
    //join thread, blocking mode
    pthread_join(tid, &ret);
    printf("exit now...%d\n", (int)ret);
    
    //pthread_exit 
    pthread_create(&tid, NULL, handler_exit, NULL);
    pthread_join(tid, &ret);
    printf("Handler_exit code is: %d\n", (int)ret);

    //thread cancel...
    sleep(3);
    pthread_create(&tid, NULL, handler_cancel, NULL);
    pthread_cancel(tid);
    pthread_join(tid, &ret);
    if(ret == PTHREAD_CANCELED)
        printf("handler func exit code is: %d\n", (int)ret);
    return 0;
}