多线程函数系列pthread_create(), pthread_join(), pthread_self()，pthread_exit(), pthread_detach()实例详解

#include <pthread.h>
int pthread_create(pthread_t *thread, const pthread_attr_t *attr, void *(*start_routine) (void *), void *arg)

创建线程，并可以向创建的线程传递一个参数（见实例3,向线程传递总的线程个数，一个int变量）；

#include <pthread.h>
int pthread_join(pthread_t thread, void **retval)

等待线程终止，并且可以获得线程的返回值；

#include <pthread.h>
pthread_t pthread_self(void);

获得线程自身的线程ID；

线程可以通过下面三种方式退出：

1.线程只是从启动例程中返回，返回值是线程的退出码；

2.线程可以被同一进程中的其它线程取消；

3.线程调用pthread_exit

#include <pthread.h>
void pthread_exit(void *retval);

终止线程，并可以向主线程返回值；

#include <pthread.h>
int pthread_detach(pthread_t thread);

在创建的线程中调用该函数，使该线程脱离进程（这里的脱离并不是真正意义上的完全脱离；脱离之后，该线程仍然在该进程空间里运行，只不过是当该线程退出的时候，它的资源会自动释放，进程不用等待其并释放其资源；

总结：

1：如何创建一个或多个线程；

2：如何在主线程中等待刚才创建的线程；

3：如何获得线程的线程ID;

4：如何在向创建的线程传递信息；

5：如何在创建的线程中退出的时候向主线程传递信息；

6：如何使线程脱离主线程；

实例1：简单的创建两个线程，并在主线程中等待这两个线程，使用pthread_create， pthread_join, pthread_self

/*************************************************************************
> File Name: create_join.cpp
> Author:
> Mail:
> Created Time: 2015年12月16日 星期三 10时41分19秒
************************************************************************/

#include<iostream>
#include <unistd.h>
#include <pthread.h>
#include <cstdlib>

using namespace std;

void *task1(void *a)
{
cout << "This is threadA..." << "thread id is " << pthread_self() << endl;
sleep(2);
cout << "threadA exit.." << endl;
}

void *task2(void *b)
{
cout << "This is threadB..." << "thread id is " << pthread_self() << endl;
sleep(2);
cout << "ThreadB exit.." << endl;
}
int main()
{
int ret;
pthread_t threadA, threadB;

ret = pthread_create(&threadA, NULL, task1, NULL);
if(ret != 0){
cout << "pthread_create error..." << endl;
exit(-1);
}
ret = pthread_create(&threadB, NULL, task2, NULL);
if(ret != 0){
cout << "pthread_create error..." << endl;
exit(-1);
}

ret = pthread_join(threadA, NULL);
if(ret != 0){
cout << "pthread_create error..." << endl;
exit(-1);
}
ret = pthread_join(threadB, NULL);
if(ret != 0){
cout << "pthread_create error..." << endl;
exit(-1);
}

cout << "main thread exit..." << endl;
exit(0);
}

实例2：创建多个线程（个数自己指定），并在主线程中等待这些线程，使用pthread_create， pthread_join, pthread_self

/*************************************************************************
> File Name: create_join.cpp
> Author:
> Mail:
> Created Time: 2015年12月16日 星期三 10时41分19秒
************************************************************************/

#include<iostream>
#include <unistd.h>
#include <pthread.h>
#include <cstdlib>

using namespace std;

void *task(void *a)
{
cout << "This is thread..." << "thread id is " << pthread_self() << endl;
sleep(2);
cout << "thread exit.." <<  pthread_self() << endl;
}

int main(int argc, char *argv[])
{
int ret;
int i = 0;
if(argc != 2){
cout << "You must input the number of thread you want to create..." << endl;
exit(-1);
}
int thread_num = atoi(argv[1]);
pthread_t threadId[thread_num];

for (i = 0; i < thread_num; ++i){
ret = pthread_create(&threadId[i], NULL, task, NULL);
if(ret != 0){
cout << "pthread_create error..." << endl;
exit(-1);
}
}

for (i = 0; i < thread_num; ++i){
ret = pthread_join(threadId[i], NULL);
if(ret != 0){
cout << "pthread_create error..." << endl;
exit(-1);
}
}

cout << "main thread exit..." << endl;
exit(0);
}

实例3：创建多个线程（个数自己指定）同时向各个线程中传递一个整数值，并在主线程中等待这些线程，使用pthread_create， pthread_join, pthread_self

/*************************************************************************
> File Name: create_join.cpp
> Author:
> Mail:
> Created Time: 2015年12月16日 星期三 10时41分19秒
************************************************************************/

#include<iostream>
#include <unistd.h>
#include <pthread.h>
#include <cstdlib>

using namespace std;

void *task(void *a)
{
int i = 0;
int * loop;
loop = static_cast<int*> (a);
for (i = 0; i < *loop; ++i){
cout <<  i+1 << ": This is thread..." << "thread id is " << pthread_self() << endl;
sleep(1);
}
cout << "thread exit.." <<  pthread_self() << endl;
}

int main(int argc, char *argv[])
{
int ret;
int i = 0;
if(argc != 2){
cout << "You must input the number of thread you want to create..." << endl;
exit(-1);
}
int thread_num = atoi(argv[1]);
pthread_t threadId[thread_num];

for (i = 0; i < thread_num; ++i){
ret = pthread_create(&threadId[i], NULL, task, (void *)&thread_num);
if(ret != 0){
cout << "pthread_create error..." << endl;
exit(-1);
}
}

for (i = 0; i < thread_num; ++i){
ret = pthread_join(threadId[i], NULL);
if(ret != 0){
cout << "pthread_create error..." << endl;
exit(-1);
}
}

cout << "main thread exit..." << endl;
exit(0);
}

实例4：创建多个线程（个数自己指定）同时向各个线程中传递一个整数值，并在主线程中等待这些线程，线程退出的时候向主线程返回值（将自身的线程id传给主线程）；

使用pthread_create， pthread_join, pthread_self， pthread_exit

/*************************************************************************
> File Name: create_join.cpp
> Author:
> Mail:
> Created Time: 2015年12月16日 星期三 10时41分19秒
************************************************************************/

#include<iostream>
#include <unistd.h>
#include <pthread.h>
#include <cstdlib>

using namespace std;

void *task(void *a)
{
int i = 0;
int * loop;
pthread_t pid = pthread_self();
loop = static_cast<int*> (a);
for (i = 0; i < *loop; ++i){
cout <<  i+1 << ": This is thread..." << "thread id is " << pid << endl;
sleep(1);
}
cout << "thread exit.." <<  pid << endl;
pthread_exit((void *)&pid);
}

int main(int argc, char *argv[])
{
int ret;
int i = 0;
if(argc != 2){
cout << "You must input the number of thread you want to create..." << endl;
exit(-1);
}
int thread_num = atoi(argv[1]);
pthread_t threadId[thread_num];

for (i = 0; i < thread_num; ++i){
ret = pthread_create(&threadId[i], NULL, task, (void *)&thread_num);
if(ret != 0){
cout << "pthread_create error..." << endl;
exit(-1);
}
}

pthread_t * pid[thread_num];
for (i = 0; i < thread_num; ++i){
ret = pthread_join(threadId[i], (void **)&pid[i]);
if(ret != 0){
cout << "pthread_create error..." << endl;
exit(-1);
}
}

for (i = 0; i < thread_num; ++i){
cout << "main thread wait the thread id is " << *pid[i] << endl;

}
cout << "main thread exit..." << endl;
exit(0);
}

实例5：创建多个线程（个数自己指定）同时向各个线程中传递一个整数值，并在主线程中等待这些线程，线程退出的时候向主线程返回值（将自身的线程id传给主线程），最要的是让线程脱离主线程；使用pthread_create， pthread_join, pthread_self， pthread_exit， pthread_detach

第一:出错的例子

/*************************************************************************
> File Name: create_join.cpp
> Author:
> Mail:
> Created Time: 2015年12月16日 星期三 10时41分19秒
************************************************************************/

#include<iostream>
#include <unistd.h>
#include <pthread.h>
#include <cstdlib>

using namespace std;

void *task(void *a)
{
int i = 0;
int * loop;
pthread_t pid = pthread_self();
pthread_detach(pid);
loop = static_cast<int*> (a);
for (i = 0; i < *loop; ++i){
cout <<  i+1 << ": This is thread..." << "thread id is " << pid << endl;
sleep(1);
}
cout << "thread exit.." <<  pid << endl;
pthread_exit((void *)&pid);
}

int main(int argc, char *argv[])
{
int ret;
int i = 0;
if(argc != 2){
cout << "You must input the number of thread you want to create..." << endl;
exit(-1);
}
int thread_num = atoi(argv[1]);
pthread_t threadId[thread_num];

for (i = 0; i < thread_num; ++i){
ret = pthread_create(&threadId[i], NULL, task, (void *)&thread_num);
if(ret != 0){
cout << "pthread_create error..." << endl;
exit(-1);
}
}

pthread_t * pid[thread_num];
for (i = 0; i < thread_num; ++i){
ret = pthread_join(threadId[i], (void **)&pid[i]);
if(ret != 0){
cout << "pthread_join error..." << i+1 << endl;
exit(-1);
}
}

for (i = 0; i < thread_num; ++i){
cout << "main thread wait the thread id is " << *pid[i] << endl;

}
cout << "main thread exit..." << endl;
exit(0);
}

第二：正确的

/*************************************************************************
> File Name: create_join.cpp
> Author:
> Mail:
> Created Time: 2015年12月16日 星期三 10时41分19秒
************************************************************************/

#include<iostream>
#include <unistd.h>
#include <pthread.h>
#include <cstdlib>

using namespace std;

void *task(void *a)
{
int i = 0;
int * loop;
pthread_t pid = pthread_self();
pthread_detach(pid);
loop = static_cast<int*> (a);
for (i = 0; i < *loop; ++i){
cout <<  i+1 << ": This is thread..." << "thread id is " << pid << endl;
sleep(1);
}
cout << "thread exit.." <<  pid << endl;
}

int main(int argc, char *argv[])
{
int ret;
int i = 0;
if(argc != 2){
cout << "You must input the number of thread you want to create..." << endl;
exit(-1);
}
int thread_num = atoi(argv[1]);
pthread_t threadId[thread_num];

for (i = 0; i < thread_num; ++i){
ret = pthread_create(&threadId[i], NULL, task, (void *)&thread_num);
if(ret != 0){
cout << "pthread_create error..." << endl;
exit(-1);
}
}

sleep(5);//必须等待，如果不等待则该进程退出，那么创建的线程也会退出
cout << "main thread exit..." << endl;
exit(0);
}

再说一个linux下写程序的一个核武器--------------man手册；