#include <iostream>using namespace std;class Singleton{
private:   Singleton();//注意:构造方法私有   virtual ~Singleton();   static Singleton* instance;//惟一实例   int var;//成员变量(用于测试)
public:   static Singleton* GetInstance();//工厂方法(用来获得实例)   int getVar();//获得var的值   void setVar(int);//设置var的值
};
//构造方法实现
Singleton::Singleton()
{   this->var = 20;   cout<<"Singleton Constructor"<<endl;
}
Singleton::~Singleton()
{if(instance != NULL){delete instance;}
}
//初始化静态成员
//Singleton* Singleton::instance=new Singleton();
Singleton* Singleton::instance=NULL;
Singleton* Singleton::GetInstance()
{   if(instance == NULL){instance = new Singleton();}return instance;
}
//seter && getter含数
int Singleton::getVar()
{   return this->var;
}
void Singleton::setVar(int var)
{   this->var = var;
}   int main(int argc, char* argv[])
{Singleton *ton1 = Singleton::GetInstance();Singleton *ton2 = Singleton::GetInstance();cout<<"ton1 var = "<<ton1->getVar()<<endl;   ton1->setVar(150);  cout<<"ton2 var = "<<ton2->getVar()<<endl;return 0;
}

#include <sys/sem.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <time.h>
#include <sys/time.h>
#include <iostream>  using namespace std;  #define MAXID  9999
static struct sembuf op_open={1,-1,0  };class GenHH{private:GenHH();//注意:构造方法私有 virtual ~GenHH();    static GenHH* instance;//惟一实例int opensem(key_t semkey);int creatsem(key_t semkey,int bigcount);int sem_open(int semid);unsigned int gen_seq();public:static GenHH* getInstance();//工厂方法(用来获得实例) unsigned int gen_hh();
}GenHH::~GenHH()
{if(instance != NULL)  {  delete instance;  }
}//初始化静态成员
GenHH* GenHH::instance=NULL;
GenHH* GenHH::getInstance()
{if(instance == NULL)  {  instance = new Singleton();  }  return instance;
}unsigned int GenHH::gen_hh()
{unsigned int hh;char   chh[9];memset(chh,0,9);sprintf(chh,"%05d%04d",time(NULL)%100000,gen_seq());hh = atoi(chh);return hh;
}unsigned int GenHH::gen_seq()
{int    seq,kid;int semid,semval;struct timeval  tv;union semun {int val;struct semid_ds *buf;unsigned short *array;} semctl_arg;kid=ftok("/etc/hosts",'m');if(kid<0){printf("system Error! Can't find  /etc/hosts!\n");gettimeofday(&tv, NULL);return tv.tv_usec % MAXID ;}semid=opensem(kid);if(semid<=0){semid=creatsem(kid,MAXID);if(semid<0){gettimeofday(&tv, NULL);return tv.tv_usec % MAXID ;}}semval=semctl(semid,1,GETVAL,0);if(semval<=2){semctl_arg.val=MAXID;if ((semctl(semid,1,SETVAL,semctl_arg)) < 0 ){gettimeofday(&tv, NULL);return tv.tv_usec % MAXID ;}}sem_open(semid);semval=semctl(semid,1,GETVAL,0);return MAXID-semval;
}int GenHH::opensem(key_t semkey)
{int semid;semid=semget(semkey,2,0);if(semid<0){printf("semaphoreid get error!\n");return -1;}return semid;
}int GenHH::creatsem(key_t semkey,int bigcount)
{int semid,semval;union semun {int val;struct semid_ds *buf;unsigned short *array;} semctl_arg;semid=semget(semkey,2,IPC_CREAT|0600);if(semid<0){return -1;}if((semval=semctl(semid,1,GETVAL,0))<0)printf("GETVAL error!\n");else if(semval==0){semctl_arg.val=1;if(semctl(semid,0,SETVAL,semctl_arg)<0)printf("SETVAL error\n");semctl_arg.val=bigcount;if(( semctl(semid,1,SETVAL,semctl_arg)) < 0 )printf("setval error\n");}return semid;
}int GenHH::sem_open(int semid)
{while(( semop(semid,&op_open,1) ) < 0 ){if( errno==EINTR ) {usleep(5000);continue;}printf("sem op_open error!\n");return -1;}return 0;
}int main(int argc, char* argv[])
{GenHH *genHH1 = GenHH::getInstance();GenHH *genHH2 = GenHH::getInstance();cout<<genHH1->gen_hh()<<endl;cout<<genHH2->gen_hh()<<endl;return 0;
}