linux 프로세스 간 통신 공유 메모리 사용

#include <stdlib.h>
#include <stdio.h>
#include <sys/shm.h>
#include <string.h>
#include <unistd.h>
#include <sys/sem.h>
#include "Ccommon.h"
union semun
{
 int val;
 struct semid_ds *buf;
 unsigned short *array;
};
//      
static int set_semvalue(void);
//     
static void del_semvalue(void);
//     
static int semaphore_p(void);
//     
static int semaphore_v(void);
static int sem_id;
int main()
{
  bool isRuning = true;
  void *pMem = NULL;
  struct shared_use_str *pshared_use_str;
  char buffer[BUFSIZ];
  int ishmid;
                   
  //     
   sem_id = semget((key_t)1234,1,0666|IPC_CREAT);
  //      
 ishmid = shmget((key_t)1234,sizeof(struct shared_use_str),0666|IPC_CREAT );
                   
   //      
   if(!set_semvalue())
   {
     fprintf(stderr,"Failed to initialize semaphore
");
     exit(-1);
   } 
                    
  if(-1 == ishmid)
  {
      printf("shmid failed
");
      exit(-1);
  }
  //      
  pMem = shmat(ishmid,(void *)0,0);
  if(pMem == (void *)-1)
  {
    printf("shmat failed
");
    exit(-1);
  }
                   
  printf("Memory Attached at %X
",pMem);
  //            
  pshared_use_str = (struct shared_use_str *) pMem;
                   
  while(true == isRuning)
  {
      //     
   if(!semaphore_p())
   {
     printf("semp p failed
");
     exit(-1);
   }
                      
     printf("enter some text
");
     fgets(buffer,BUFSIZ,stdin);
                      
//              strncpy(pshared_use_str->somedate,buffer,TEXT_SIZE);
     pshared_use_str->iwrite_by_you = 1;
     if(strncmp(buffer,"end",3) == 0)
     {
       isRuning = 0;
    } 
                     
    //     
   if(!semaphore_v())
   {
     printf("failed to set v 
");
     exit(-1);
   } 
  } 
                   
  //          
   sleep(3);
     //     
   del_semvalue();
   //      
  if(shmdt(pMem) == -1)
  {
    printf("shmdt failed
");
    return -1;
  } 
                   
  return 0;
}
static int set_semvalue(void)
{
 union semun sem_unition;
 sem_unition.val = 1;
 //      ，       1
 if(semctl(sem_id,0,SETVAL,sem_unition) == -1)
 {
   printf("faile to semctl
");
   return -1;
 } 
 return 1;
}
static void del_semvalue(void )
{
 union semun sem_unition;
 //     
 if(semctl(sem_id,0,IPC_RMID,sem_unition) == -1)
 {
   printf("failed to semctl
");
   return;
 } 
}
static int semaphore_p(void )
{
 struct sembuf sem_b;
 sem_b.sem_num = 0;
 sem_b.sem_op = -1;
 sem_b.sem_flg = SEM_UNDO;
//      ，    1  ，    0    。        
if(-1 == semop(sem_id,&sem_b,1))
 {
   printf("semaphore failed
");
   return 0;
 } 
 return 1;
}
static int semaphore_v(void )
{
 struct sembuf sem_b;
 sem_b.sem_num = 0;
 sem_b.sem_op = 1;
 sem_b.sem_flg = SEM_UNDO;
//      ，    1  ，     0    。        
 if(-1 == semop(sem_id,&sem_b,1))
 {
   printf("semaphore failed
");
   return 0;
 } 
 return 1;
}

#include <stdlib.h>
#include <stdio.h>
#include <sys/shm.h>
#include <string.h>
#include <unistd.h>
#include "Ccommon.h"
#include <sys/sem.h>
union semun
{
 int val;
 struct semid_ds *buf;
 unsigned short *array;
};
//      
static int set_semvalue(void);
//     
static void del_semvalue(void);
//     
static int semaphore_p(void);
//     
static int semaphore_v(void);
static int sem_id;
int main()
{
  bool isRuning = true;
  void *pMem = NULL;
  struct shared_use_str *pshared_use_str;
  int ishmid;
    
    //     
   sem_id = semget((key_t)1234,1,0666|IPC_CREAT);
   //      
  ishmid = shmget((key_t)1234,sizeof(struct shared_use_str),0666|IPC_CREAT);
    
  if(-1 == ishmid)
  {
      printf("shmid failed
");
      exit(-1);
  }
  //      
  pMem = shmat(ishmid,(void *)0,0);
  if(pMem == (void *)-1)
  {
    printf("shmat failed
");
    exit(-1);
  }
    
  printf("Memory Attached at %X
",pMem);
    
  pshared_use_str = (struct shared_use_str *) pMem;
  pshared_use_str->iwrite_by_you = 0;
    
  while(true == isRuning)
  {
         //     
   if(!semaphore_p())
   {
     printf("semp p failed
");
     exit(-1);
   }
    printf("you write %s
",pshared_use_str->somedate);
    sleep(rand()%5);
    pshared_use_str->iwrite_by_you = 0;
    if(strncmp(pshared_use_str->somedate,"end",3) == 0)
    {
      isRuning = false;
    } 
     if(!semaphore_v())
   {
     printf("failed to set v 
");
     exit(-1);
   } 
  } 
  //      
  if(shmdt(pMem) == -1)
  {
    printf("shmdt failed
");
    exit(-1);
  } 
  //      
  if(shmctl(ishmid,IPC_RMID,0) == -1)
  {
    printf("shmctl failed
");
    exit(-1);
  } 
    
  return 0;
}
static void del_semvalue(void )
{
 union semun sem_unition;
 //     
 if(semctl(sem_id,0,IPC_RMID,sem_unition) == -1)
 {
   printf("failed to semctl
");
   return;
 } 
}
static int semaphore_p(void )
{
 struct sembuf sem_b;
 sem_b.sem_num = 0;
 sem_b.sem_op = -1;
 sem_b.sem_flg = SEM_UNDO;
//      ，    1  ，    0    。        
if(-1 == semop(sem_id,&sem_b,1))
 {
   printf("semaphore failed
");
   return 0;
 } 
 return 1;
}
static int semaphore_v(void )
{
 struct sembuf sem_b;
 sem_b.sem_num = 0;
 sem_b.sem_op = 1;
 sem_b.sem_flg = SEM_UNDO;
//      ，    1  ，     0    。        
 if(-1 == semop(sem_id,&sem_b,1))
 {
   printf("semaphore failed
");
   return 0;
 } 
 return 1;
}