void initiate(char ** argv){
  int key2 = ftok("makefile",'e');
    //creating
  if (strcmp(argv[1], "--create") == 0){
    createsharedmem(key2);
    createsem(key2);
    createfile("story.txt");
    printf("INITIATED\n");
  }
  //removing
  else if (strcmp(argv[1], "--remove") == 0) {
    //remove the shared memory (we need to remove pointers to memories separately or else shared memory will not disappear)
    removesharedmem(key2);
    //remove the semaphore
    removesem(key2);
    //display the file
    if (filesize() >0){
      int fd;
      fd = open("story.txt", O_RDWR | O_APPEND, 0644);
      write(fd, "\n",2);
    }
    //Display the full contents of the story 
    execlp("cat","cat","story.txt",NULL);
  }
  else{
   printf("INVALID INPUT: Please run control with either '--create' or '--remove'.\n");//
  } 
}
Exemple #2
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int main (int argc,char* argv[])
{
    //main ss
    int semid,shmid;
    char *shmaddr;
    char write_str[SHM_SIZE];
    memset(write_str,SHM_SIZE,'\0'); 
    if ((shmid = createshm(".",'m',SHM_SIZE)) == -1) { 
        exit(-1);
    } 

    if((shmaddr = shmat(shmid,(char*)0,0)) == (char*)-1)
    {
        cout << "shmat error" << endl;
    }
   if((semid =(createsem(".",'s',1,1)))==-1)
   {
       exit(-1);
   }

   while(1)
   {
       wait_sem(semid,0);
       sem_P(semid,0);
       cout << "writer:"<< "do something here" << endl;
       fgets(write_str,1024,stdin);
       int length = strlen(write_str);
       write_str[len]='\0';
       strncpy(shmaddr,write_str,len+1);
       sleep(10);
   }
    return 0;
}
int diningphilosopher()
{
	status= shmat(shmid, (void *)0, 0);
	
	for(int i=0;i<N;i++)
		{
		createsem(i);
		}

for(int i=0;i<N; i++)
		
		{
		// All the philosophers are thinking initially
		status[i]=THINKING;
		}


for(int i=0;i<N;i++)
	
		{
			int a =fork();
				if(a!=0)
					{
					
					// I am in the parent 
					
					}
				else
			       {
					down(i);
					philosopher(i);
					printf("status of philosopher %d = %d\n", i+1, status[i]);
					}

		}
		
		return 0;
		
		} // end of dining philosopher function