print_do.h

入门程序

#include <stdio.h>
#include<sys/types.h>
#include<sys/ipc.h>
#include<sys/sem.h>
#include<sys/shm.h>

#define	shmsz	32				/* 共享内存大小*/
#define	shm_key	4588			/* 共享内存KEY值*/

int shmid;
char	*shm;
/* char	*shmat(); */

void	create_shm();
void	delete_shm();
void	get_shm();
void	at_shm();

void	create_shm()			/*	create共享内存shmid	*/
{
	if(shmid=shmget(shm_key,shmsz,IPC_CREAT|0666)==-1)
	{
		perror("Create share memory error");
		exit(1);
	}
}

void	get_shm()				/*	获取共享内存shmid	*/
{
	if((shmid=shmget(shm_key,shmsz,0666))==-1)
	{
		perror("Get share memory error");
		exit(1);
	}
}

void	at_shm()				/*	附加共享内存shmid	*/
{
	if((shm=shmat(shmid,NULL,0))==(char *)-1)
	{
		perror("at share memory error");
		exit(1);
	}
}

void	delete_shm()				/*	删除共享内存shmid		*/
{
	if(shmctl(shmid,IPC_RMID,0)==-1)
	{
		perror("Remove share memory error");
		exit(1);
	}
}