共享内存 shm.h http://ciaos.iteye.com/blog/1860119

attach_shm.c

//attach_shm.c  
#include<sys/types.h>  
#include<sys/ipc.h>  
#include<sys/shm.h>  
#include<stdio.h>  
  
#define BUFSZ 1024  
  
int main()  
{  
        int *shm;  
        shm = shmat(131072,NULL,0);  
        if(*shm == -1){  
                printf("shmat failed\n");  
                return -1;  
        }  
        printf("attach shared memory succeed: %d\n",*shm);  
        system("ipcs -m"); //查看共享内存调用状态   
        if(shmdt(shm) == -1){  
                printf("shmdt failed\n");  
                return -1;  
        }  
        system("ipcs -m"); //查看共享内存调用状态   
        return 0;  
}  

create_shm.c

//create_shm.c  
#include<sys/types.h>  
#include<sys/ipc.h>  
#include<sys/shm.h>  
#include<stdio.h>  
  
#define BUFSZ 1024  
  
int main()  
{  
        int shm_id;     //共享内存ID  
        shm_id = shmget(IPC_PRIVATE,BUFSZ,0666);  
        if(shm_id < 0){  
                printf("shmget failed\n");  
                return -1;  
        }  
        printf("create shared memory succeed: %d\n",shm_id);  
        system("ipcs -m"); //查看共享内存ID  
        return 0;  
}  

read_shm.c

//read_shm.c  
#include<sys/types.h>  
#include<sys/ipc.h>  
#include<sys/shm.h>  
#include<stdio.h>  
  
typedef struct  
{  
        char name[4];  
        int age;  
}people;  
  
int main()  
{  
        int i;  
        char *t = 'a';  
        people *p_shm = NULL;  
        p_shm = shmat(131072,NULL,0);  
        if(p_shm == NULL){  
                printf("shmat failed\n");  
                return -1;  
        }  
        for(i=0;i<5;i++) {  
                printf("name:%s age:%d\n",(*(p_shm+i)).name,(*(p_shm+i)).age);  
        }  
        if(shmdt(p_shm) == -1){  
                printf("shmdt failed\n");  
                return -1;  
        }  
        return 0;  
}

remove_shm.c

//attach_shm.c  
#include<sys/types.h>  
#include<sys/ipc.h>  
#include<sys/shm.h>  
#include<stdio.h>  
  
int main()  
{  
        shmctl(131072, IPC_RMID, NULL);  
        return 0;  
}  

write_shm.c

//write_shm.c  
#include<sys/types.h>  
#include<sys/ipc.h>  
#include<sys/shm.h>  
#include<stdio.h>  
  
typedef struct  
{  
        char name[4];  
        int age;  
}people;  
  
int main()  
{  
        int i;  
        char *t = 'a';  
        people *p_shm = NULL;  
        p_shm = shmat(131072,NULL,0);  
        if(p_shm == NULL){  
                printf("shmat failed\n");  
                return -1;  
        }  
        for(i=0;i<5;i++) {  
                t += 1;  
                memcpy((*(p_shm+i)).name,&t,1);  
                (*(p_shm+i)).age = 20+i;  
        }  
        if(shmdt(p_shm) == -1){  
                printf("shmdt failed\n");  
                return -1;  
        }  
        return 0;  
}

http://javagoo.tk/java/shared_memory.html