pc_create

#include <sys/types.h>#include <sys/ipc.h>#include <sys/shm.h>#include <stdio.h>#include <stdlib.h>#include <errno.h>extern int errno;	char *buffer;int main ( int argc, char *argv[] ){		key_t key;	int shmid;		int size;	/*size of buffer*/	int id;	int semaphoreSet;	if ( argc !=  2 ) 	{		fprintf(stderr, "Usage: <.out> <N>\n");		exit(-1);	}		size = atoi(argv[1]) * sizeof(double);	id = 9999;	/* make the key        if ((key = ftok("pc_create.c", 'P')) == -1) 	{            fprintf(stderr, "ftok error. errno is: %d\n", errno);            exit(1);        }/*	/* connect to the segment: */        if ((shmid = shmget(id, size, IPC_CREAT)) == -1) 	{            fprintf(stderr, "shmget error. errno is: %d\n", errno);            exit(1);        }	if((buffer = shmat(shmid, NULL, 0)) < 0) 	{		fprintf(stderr, "shmat error. errno is: %d\n", errno);		exit(1);	}	/* semaphore */	semaphoreSet = semget(id, 1, IPC_CREAT);	If ( semaphoreSet == -1)	{		fprintf("semget error");		exit(1);	}		/*printf("%d\n", shmid);*/return 0;}