linux共享内存使用实例

三个文件，一个头文件，一个读，一个写，用同一个key值申请共享内存。
//shm.h
#ifndef _SHM_COM_H
#define _SHM_COM_H 1
#define TEXT_SZ 2048
struct shared_use_at
{
    int written_by_you;
    char some_text[TEXT_SZ];
};
struct kts
{
 int power;
 int mode;
 int temp;
 int windspeed;
 int write_flag;
};
#endif
//shm_write.c
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include "shm.h"
int main()
{
 int running = 1;
 void *shared_memory = (void *)0;
 struct shared_use_at *shared_stuff;
 char buffer[BUFSIZ];
 int shmid;
    shmid = shmget((key_t)1234, sizeof(struct shared_use_at), 0666 | IPC_CREAT);
    if(shmid == -1)
    {
 fprintf(stderr, "shmget failed\n");
 exit(EXIT_FAILURE);
    }
    shared_memory = shmat(shmid, (void *)0, 0);
    if(shared_memory == (void *)-1)
    {
        fprintf(stderr, "shmat failed\n");
        exit(EXIT_FAILURE);
    }
    printf("Memory attached at %X\n", (int)shared_memory);
    shared_stuff = (struct shared_use_at *)shared_memory;
    while(running)
    {
        while(shared_stuff->written_by_you == 1)
        {
            sleep(1);
            printf("waiting for client...\n");
        }
        printf("Enter some text: ");
      &n