【操作系统】多线程和多进程的管理

一、实验目的

加深对进程概念的理解，明确进程与线程的区别。
掌握Linux进程创建和撤销的方法，进一步认识并发执行的实质。
了解多线程的程序设计方法。

二、实验项目内容

多进程和多线程
 1号进程创建2，3号两个进程
 2号进程创建两个线程Thread1，Thread2
 Thread1：求（1~n）之间的素数
 Thread2：生成Fibonacci序列
 3号进程创建4，5号两个进程
 4号进程执行系统命令，ls，ps，cp等
 5号进程执行一个用户编写的可执行文件
 每个进程输出自己的进程ID和父进程的进程ID，观察分析，并画出程序的进程树结构。

三、实验程序代码：

#include <stdio.h>#include <math.h>#include <sys/types.h>  #include <sys/wait.h>#include <unistd.h>#include <stdlib.h>#include <pthread.h>/*** Attention to add -lpthread and -lm when compile* eg : gcc process.c -lpthread -lm -o process*///The thread to find the prime number between (1~n)void *MyThread1(void* arg){    int n;    //Get the resolve range    printf("input the value of n:\n");    scanf("%d",&n);    printf("the prime number between 1~%d is:\n",n);    for(int m=2;m<=n;m++)    {        if (m<=3)        {            printf("%4d",m);            continue;          }       int k=sqrt(m);         for(int i=2; i<=k; i++)       {            // printf("m: %f\n",k);            if(m%i==0)                 break;              if(i>=k)                 printf("%4d",m);         }    }    printf("\n thread1 exit!\n");    pthread_exit(0);}//The thread to generate Fibonacci sequencesvoid *MyThread2(void* arg){    int fib0=0,fib1=1,fib2,i,N;    printf("input fib value N:\n");    scanf("%d",&N);    printf("the fib sequences as following:\n");    for (int i = 0; i < N; i++)    {        if (i==0)        {            printf("0");        }        else if (i==1)        {            printf("1");        }        else        {            fib2=fib0+fib1;            printf("%d",fib2 );            fib0=fib1;            fib1=fib2;        }    }    printf("\n thread2 exit!\n");    pthread_exit(0);}//No.2 process create two threadsint createThread(){    int ret1=0,ret2=0;    //Define the id of thread    pthread_t id1,id2;    //Create thread1    ret1=pthread_create(&id1,NULL,MyThread1,NULL);    if (ret1)    {        printf("Create pthread error!\n");        return 1;    }    //Create thread2    ret2=pthread_create(&id2,NULL,MyThread2,NULL);    if (ret2)    {        printf("Create pthread error\n");        return 1;    }    //Mainthread wait for childthread    pthread_join(id1,NULL);    pthread_join(id2,NULL);    printf("main thread exit!\n");    return 0;}//The Function of N0.4 and No.5void childProcessfunc(int i){    switch(i)    {        case 4:            printf("\nThis is NO.4 process, ID is  %d, parent ID is %d, will create 2 thread\n",getpid(),getppid());            printf("\nExcute system command ls:\n");            system("ls");            printf("\nExcute system command ps:\n");            system("ps");            printf("\nExcute system command cp:\n");            system("cp sayhello.c sayhello.cpp");            break;        case 5:            printf("\nThis is NO.5 process, ID is  %d, parent ID is %d, will create 2 thread\n",getpid(),getppid());            printf("\nCarray out executable program:\n");            system("./sayhello");            break;    }    exit(0);}//No.3 process create two child process, N0.4 and No.5int createProcess(){    int i;    for (int i = 4; i <= 6; i++)    {        pid_t child=fork();        //create process failed        if (child==-1)            {            printf("Error hanppened in fork function!\n");            return 0;        }        //exert function when success        else if(child==0)        {            childProcessfunc(i);        }    }    for (int i = 0; i < 2; i++)    {        //Parent process waits child process        pid_t tempPid=wait(NULL);        printf("The process %d exit\n", tempPid);    }    return 0;}//The Function of N0.2 and No.3void mainProcessfunc(int i){    switch(i)    {        case 2:            printf("\nThis is NO.2 process, ID is  %d, parent ID is %d, will create 2 thread\n",getpid(),getppid());            createThread();            break;        case 3:            printf("\nThis is NO.3 process, ID is  %d, parent ID is %d, will create 2 thread\n",getpid(),getppid());            createProcess();            break;    }    exit(0);}int main(){    int i;    //Create two child process, No.2 and No.3    for (int i = 2; i < 4; i++)    {        pid_t child=fork();        if (child==-1)        {            printf("Error happened in fork function!\n");            return 0;        }        else if(child==0)        {            // printf("process Id is %d:\n",getpid());            mainProcessfunc(i);        }    }    for (int i = 0; i < 2; i++)    {        //Parent process waits child process        pid_t tempPid=wait(NULL);        printf("\nThe process %d exit\n", tempPid);    }    //Root process exit    printf("\nThe No.1 root process Id is %d exit\n",getpid());    return 0;}

注：在编译命令中添加-lpthread和 -lm ，-lpthread是表示要连接到pthread的库是这里省略的lib，因为在求素数算法中使用math库中sqrt函数，需要用到math.h，则加上 -lm。

四、实验结果