非亲缘进程间的共享内存与信号通信

/*****************************

写入数据到共享内存,后再得到另一个进程pid
向其发送SIGUSR1信号,另一个进程
收到后退出

***************************/

#include<sys/shm.h>
#include<sys/ipc.h>
#include<stdio.h>
#include<stdlib.h>
#include<unistd.h>
#include<signal.h>
#include<sys/types.h>
#include<sys/stat.h>
#include<string.h>
#include<errno.h>
#define SIZE 1024

int main(void)
{
sleep(2);
char *addr;
char buf[50];
int shmid;

printf("please input string to share memory\n");
fgets(buf,100,stdin);

key_t key;
key = ftok(".",'a');
printf("key = %d\n",(int)key);
if((shmid = shmget(key,SIZE,0666|IPC_CREAT)) < 0)
perror("shmget");
else{
printf("get share memory success\n");
printf("shmid = %d\n",shmid);
}

addr = shmat(shmid,NULL,0);
if( addr == (void *)(-1))
perror("shmat");
else{
printf("get addr success\n");
printf("addr = %p\n",addr);
}

strcpy(addr+4,buf);

pid_t pid;
strncpy(&pid,addr,4);

kill(pid,SIGUSR1);

if(shmdt(addr) < 0)
perror("shmdt");
else
printf("detached share memory\n");
return 0;

}

/************************

先写入自己的pid 对方写完数据后
向 自己 发送一SIGUSR1信号,收到
信号后,读数据后退出.

**********************/
#include<sys/shm.h>
#include<sys/ipc.h>
#include<stdio.h>
#include<stdlib.h>
#include<unistd.h>
#include<signal.h>
#include<sys/types.h>
#include<sys/stat.h>
#include<string.h>
#include<errno.h>
#define SIZE 1024

void get(int sig);
int main(void)
{
char *addr;
char buf[50];
int shmid;
signal(SIGUSR1,get);

key_t key;

key = ftok(".",'a');
printf("key = %d\n",key);

shmid = shmget(key,SIZE,0666|IPC_CREAT);
if(shmid < 0)
perror("shmget");
else{
printf("get share memory success\n");
printf("shmid = %d\n",shmid);
}

addr = shmat(shmid,NULL,0);
if(addr == (void *)(-1))
perror("shmat");
else{
printf("get addr success\n");
printf("addr = %p\n",addr);
}

pid_t pid = getpid();
strncpy(addr,&pid,4);

pause();
strcpy(buf,addr+4);
fprintf(stdout,"get message from shm:\n%s\n",buf);

if(shmdt(addr)<0)
perror("shmdt");
else
printf("detached share memory success\n");

if (shmctl(shmid, IPC_RMID, NULL) == -1)
perror("Child: shmctl(IPC_RMID)\n");
else
printf("Delete shared-memory\n");

return 0;

}

void get(int sig)
{
}