c/c++ 服务后台父进程监控子进程退出后重新执行

#include <iostream>
#include <unistd.h>
#include <stdlib.h>
#include <signal.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/wait.h>
using namespace std;
class CChild{
    private:
        int value;
        pid_t pid;
    public:
        CChild(int i){value=i;}
        CChild(){value=0;}
        int getValue(){
            return value;
        }
        void setValue(int varValue){
            value=varValue;
        }
        int getPid(){
            return pid;
        }
        void setPid(int varPid){
            pid=varPid;
        }
        int start(){
            pid_t _pid;
            _pid=fork();
            printf("start child process:fork():%d\n",_pid);
            if(_pid>0){
                pid=_pid;
                return 0;
            }
            else if(_pid <0){
                pid=_pid;
                return -1;
            }else if(_pid == 0){
                pid=getpid();
                for(;;){
                    sleep(20);
                    printf("child process!value:%d,\tpid:%d\n",value,pid);
                }
            }
        }
};
CChild cc[10]={0,1,2,3,4,5,6,7,8,9};
int log(char* str){
    FILE *logfile;
    logfile = fopen("/tmp/liveser.log","a+");
    fputs(str,logfile);
    fclose(logfile);
}
void child_quit(int sig){
    int _pid,status;
    char str[512];
    _pid=wait(&status);
    sprintf(str,"child exit!pid:%d",_pid);
    log(str);
    for(int i=0;i<9;i++)
    {
        if(_pid == cc[i].getPid())
        {
        cc[i].start();
        }
    }
}
int startMainServer(CChild *cc){
    signal(SIGCHLD, child_quit);
    int i,_cid;
    for(i=0;i<9;i++){
        printf("start child process:%d\n",i);
        cc[i].start();
    }
    for(;;){
        for(i=0;i<9;i++){
            sleep(60);
            printf("child %d is run!",cc[i].getPid());
        }
    }
}
int main()
{
    //CChild cc[10]={0,1,2,3,4,5,6,7,8,9};
    cout << "Hello world!" << endl;
    int i=daemon(0,0);
    if(i==0){startMainServer(cc);}
    if(i != 0){
        exit(0);
    }
    return 0;
}