linux：共享内存

#include <sys/ipc.h>
#include <sys/shm.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <iostream>
using namespace std;
struct shared_use_st
{
int flags;
char buff[1000];
};
int main()
{
void *shared_memory = NULL;
int shmid = shmget((key_t)1234,sizeof(shared_use_st),0666|IPC_CREAT);
if(shmid==-1)
{
fprintf(stderr,"shmget failed\n");
exit(0);
}

shared_memory = shmat(shmid,(void *)0,0);
if(shared_memory==(void *)-1)
{
printf("Error");
exit(0);
}
printf("Memory attached at %x\n",(int)shared_memory);

shared_use_st *shared_buff = (shared_use_st*)shared_memory;
shared_buff->flags = 0;
if(fork()==0)
{
while(1)
{
while(shared_buff->flags==0)
{
strncpy(shared_buff->buff,"liuhuiyan",10);
shared_buff->flags = 1;
sleep(1);
}
}
}
else
{
while(1)
{
while(shared_buff->flags==1)
{
char data_buff[100];
strcpy(data_buff,shared_buff->buff);
cout<<data_buff<<endl;
shared_buff->flags=0;
}
}
}
shmdt(shared_memory);
return 0;
}