消息队列

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/msg.h>
#include <unistd.h>
#include <sys/ipc.h>

void msg_show_attr(int msg_id, struct msqid_ds msg_info)
{
int ret = -1;
sleep(1);
ret = msgctl(msg_id, IPC_STAT, &msg_info);
if( -1 == ret)
{
printf(“获得消息信息失败\n”);
return ;
}

printf(“\n”);
printf(“现在队列中的字节数：%d\n”,msg_info.msg_cbytes);
printf(“队列中消息数：%d\n”,msg_info.msg_qnum);
printf(“队列中最大字节数：%d\n”,msg_info.msg_qbytes);
printf(“最后发送消息的进程pid：%d\n”,msg_info.msg_lspid);
printf(“最后接收消息的进程pid：%d\n”,msg_info.msg_lrpid);
printf(“最后发送消息的时间：%s”,ctime(&(msg_info.msg_stime)));
printf(“最后接收消息的时间：%s”,ctime(&(msg_info.msg_rtime)));
printf(“最后变化时间：%s”,ctime(&(msg_info.msg_ctime)));
printf(“消息UID是：%d\n”,msg_info.msg_perm.uid);
printf(“消息GID是：%d\n”,msg_info.msg_perm.gid);
}
int main(void)
{
int ret = -1;
int msg_flags, msg_id;
key_t key;
struct msgmbuf{
int mtype;
char mtext[10];
};
struct msqid_ds msg_info;
struct msgmbuf msg_mbuf;

int msg_sflags,msg_rflags;
char *msgpath = “/ipc/msg/”;
key = ftok(msgpath,’a');
if(key != -1)
{
printf(“成功建立KEY\n”);
}
else
{
printf(“建立KEY失败\n”);
}

msg_flags = IPC_CREAT;
msg_id = msgget(key, msg_flags|0666);
if( -1 == msg_id)
{
printf(“消息建立失败\n”);
return 0;
}
msg_show_attr(msg_id, msg_info);

msg_sflags = IPC_NOWAIT;
msg_mbuf.mtype = 10;
memcpy(msg_mbuf.mtext,”测试消息”,sizeof(“测试消息”));
ret = msgsnd(msg_id, &msg_mbuf, sizeof(“测试消息”), msg_sflags);
if( -1 == ret)
{
printf(“发送消息失败\n”);
}
msg_show_attr(msg_id, msg_info);

msg_rflags = IPC_NOWAIT|MSG_NOERROR;
ret = msgrcv(msg_id, &msg_mbuf, 10,10,msg_rfla