21 semaphore 3

来源：互联网发布：windows不激活编辑：程序博客网时间：2024/05/18 19:35

1. 示例，多进程间信号灯通信：

需要先执行Client程序，再执行Server。

Server端程序

#include "stdio.h"#include "stdlib.h"#include "pthread.h"//#include "semaphore.h"#include "sys/ipc.h"#include "sys/sem.h"#include "unistd.h"//sem_t sem;union semun {                int  val;  /* Value for SETVAL*/struct semid_ds *buf;    /* Buffer for IPC_STAT, IPC_SET */                  unsigned short  *array;  /* Array for GETALL, SETALL */                 struct seminfo  *__buf;  /* Buffer for IPC_INFO(Linux-specific) */};int semid;union semun mysemun;struct sembuf mysembuf;int main()//main thread code{  int i;  int key;  key=ftok("./a.c",'a');  if(key < 0)  {printf("creat key failure\n");return -1;  }  printf("creat key sucess \n");  semid=semget(key,3,IPC_CREAT | 0777);//IPC_EXCL  if(semid < 0)  {printf("creat semaphore failure\n");return -2;  }  printf("creat semaphore sucess,semid=%d\n",semid);  system("ipcs -s");  //init sem  //mysemun.val=0;  //semctl(semid,0,SETVAL,mysemun);  mysembuf.sem_num=0;  mysembuf.sem_flg=0;  for(i=0;i<10;i++)//first   {usleep(100);printf("this is main fun i=%d\n",i);  }  //V  mysembuf.sem_op=1;  semop(semid,&mysembuf,1);  while(1);  return 0;}

执行结果：

alex@alex-VirtualBox:~/Share/process/twenty-one$ ./servercreat key sucesscreat semaphore sucess,semid=65537------ Semaphore Arrays --------key        semid      owner      perms      nsems0x00000000 32768      alex       777        30x6101657b 65537      alex       777        3this is main fun i=0this is main fun i=1this is main fun i=2this is main fun i=3this is main fun i=4this is main fun i=5this is main fun i=6this is main fun i=7this is main fun i=8this is main fun i=9

Client端程序

#include "stdio.h"#include "stdlib.h"#include "pthread.h"//#include "semaphore.h"#include "sys/ipc.h"#include "sys/sem.h"#include "unistd.h"//sem_t sem;union semun {                int  val;  /* Value for SETVAL*/struct semid_ds *buf;    /* Buffer for IPC_STAT, IPC_SET */                  unsigned short  *array;  /* Array for GETALL, SETALL */                 struct seminfo  *__buf;  /* Buffer for IPC_INFO(Linux-specific) */};int semid;union semun mysemun;struct sembuf mysembuf;int main()//main thread code{  int i;  int key;  key=ftok("./a.c",'a');  if(key < 0)  {printf("creat key failure\n");return -1;  }  printf("creat key sucess \n");  semid=semget(key,3,IPC_CREAT | 0777);//IPC_EXCL  if(semid < 0)  {printf("creat semaphore failure\n");return -2;  }  printf("creat semaphore sucess,semid=%d\n",semid);  system("ipcs -s");  //init sem  mysemun.val=0;  semctl(semid,0,SETVAL,mysemun);  mysembuf.sem_num=0;  mysembuf.sem_flg=0;  //P   wait  mysembuf.sem_op=-1;  semop(semid,&mysembuf,1);  for(i=0;i<10;i++)//second   {usleep(100);printf("this is main fun i=%d\n",i);  }  //V  //mysembuf.sem_op=1;  //semop(semid,&mysembuf,1);  while(1);  return 0;}

执行结果：

alex@alex-VirtualBox:~/Share/process/twenty-one$ ./clientcreat key sucesscreat semaphore sucess,semid=65537------ Semaphore Arrays --------key        semid      owner      perms      nsems0x00000000 32768      alex       777        30x6101657b 65537      alex       777        3this is main fun i=0this is main fun i=1this is main fun i=2this is main fun i=3this is main fun i=4this is main fun i=5this is main fun i=6this is main fun i=7this is main fun i=8this is main fun i=9

0 0