test_lg_2.c

多用户银行系统

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

#define SHM_MODE (SHM_W | SHM_R)
int main(){
	
	key_t key;
	char name[10];
	int shmid;
	
	if((key = ftok("../src/test_lg.c" , 'a')) == -1){
		printf("ftok error!\n");
		exit(1);	
	}
/*
	key = shmget(key , sizeof name , SHM_MODE);	
	if(!key){
		printf("shmget error!\n");
		exit(1);	
	}
	printf("key is : %p\n" , key);
	
*/
	printf("key form ftok is : %p\n" , key);
	//if((shmid = shmget(key , sizeof name , SHM_MODE)) == -1){
	if((shmid = shmget(key , sizeof name , IPC_CREAT)) == -1){
		printf("get shm error!\n");
		exit(1);	
	}
	char *s;
	char *a;
	s = (char *)shmat(shmid , NULL , 0);
	printf("a is : %s\n",a);
	strcpy(s , "laoguai");
	a = (char *)shmat(shmid , NULL , 0);
	printf("a is : %s\n" , a);
	shmdt((void *)a);
	sleep(1);
}