fork 出来的多个子进程 如何样能 wait 不同的时间

fork 出来的多个子进程 怎么样能 wait 不同的时间

C/C++ code

#include <iostream>#include <stdlib.h>#include <unistd.h>#include <sys/types.h>#include <sys/wait.h>#include <errno.h>#include <string.h>#include <time.h>using namespace std;int main(){    srand(time(NULL));    int status,i;    pid_t apid;    for (i = 0; i < 10; i++)    {        status = fork();        if (status == 0 || status == -1) break;    }    if (status == -1)    {        //error        cout << "error" << endl;    }    else if (status == 0)    {        //sub process        pid_t cpid;        cpid = getpid();        cout << "in child " << i <<" pid= "<< cpid << endl;        int msec;        msec = rand()%1000000;        usleep(msec);        exit(0);    }    else    {        //parent process        apid=wait(&status);        cout << "apid= " << apid << endl;    }         return 0;}

按照上面的程序 我想让每一个子进程 在输出自己的 pid和顺序之后 都随机停止一段时间。
这样 wait（）得到的 返回子进程的 pid就不会总是第一个了


但是实际情况是 在输出所有pid 和 i之后 程序才停止。。 
wait 返回的pid总是第一个fork出来的 子进程pid  

怎么能解决？

[解决办法]
楼主还不明白rand的用法

C/C++ code

#include <iostream>#include <stdlib.h>#include <unistd.h>#include <sys/types.h>#include <sys/wait.h>#include <errno.h>#include <string.h>#include <time.h>using namespace std;int main(){    srand(time(NULL));    int status,i;    pid_t apid;    for (i = 0; i < 10; i++)    {        status = fork();        if (status == 0 || status == -1) break;    }    if (status == -1)    {        //error        cout << "error" << endl;    }    else if (status == 0)    {        //sub process        pid_t cpid;        cpid = getpid();        cout << "in child " << i <<" pid= "<< cpid << endl;        int msec;        // Add the following three lines        time_t tick;        tick = time(0);        srand((tick << 16) | (getpid() & 0xffff));        msec = rand()%1000000;        // Add the following line to check the msec        cout << "msec = " << msec << endl;        usleep(msec);        exit(0);    }    else    {        //parent process        apid=wait(&status);        cout << "apid= " << apid << endl;    }         return 0;} 

 

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