linuxC多进程通信_systemV消息队列---进程间通讯实例

给消息队列写入消息

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

#define MSG_TYPE1 1
#define MSG_TYPE2 2

struct msgbuf
{
	long mtype;
	char mtext[80];
};

int main (void)
{
//	key_t key = ftok (".", 510);
	key_t key = 12345;
	int msg_id = msgget (key, IPC_CREAT | 0666);
	struct msgbuf msg;
	memset (&msg, 0, sizeof(msg));

	msg.mtype = MSG_TYPE2;
	strncpy (msg.mtext, "hello world\n", 80);

	if (msgsnd (msg_id, (void *)&msg,  \
                strlen (msg.mtext), 0) == -1)
	{
		perror ("msgsnd");
		exit (EXIT_FAILURE);
	}

	return 0;
}

读取消息队列中的消息

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

#define MSG_TYPE1 1
#define MSG_TYPE2 2

struct msgbuf
{
	long mtype;
	char mtext[80];
};

int main (int argc, char *argv[])
{
//	key_t key = ftok (".", 510);
	key_t key = 12345;
	int msg_id = msgget (key, IPC_CREAT | 0666);

	struct msgbuf msg;
	memset (&msg, 0, sizeof(msg));
	if (msgrcv (msg_id, (void *)&msg,  \
                sizeof(msg.mtext), MSG_TYPE2, 0) == -1)
	{
		perror ("msgrcv");
		exit (EXIT_FAILURE);
	}
	printf ("%s", msg.mtext);
	msgctl (msg_id, IPC_RMID, NULL);

	return 0;
}

修改消息队列中的消息属性

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

#define handle_error(msg) \
    {perror(msg);exit(EXIT_FAILURE);}

int main (void)
{
//	key_t key = ftok (".", 510);
	key_t key = 12345;
	int msg_id = msgget (key, IPC_CREAT | 0666);

	struct msqid_ds info;
	if (msgctl (msg_id, IPC_STAT, &info) == -1)
        handle_error("msgctl");
	printf ("uid:%d, gid:%d, cuid:%d, cgid:%d\n", info../.uid, \
			info.msg_perm.gid, info.msg_perm.cuid, info.msg_perm.cgid);
	printf ("mode:%03o, cbytes:%lu, qnum:%lu, qbytes:%lu\n", \
			info.msg_perm.mode & 0777, info.msg_cbytes,  \
			info.msg_qnum, info.msg_qbytes);

	info.msg_qbytes = 16380;
	if (msgctl (msg_id, IPC_SET, &info) == -1)
        handle_error("msgctl");
	if (msgctl (msg_id, IPC_STAT, &info) == -1)
        handle_error("msgctl");
	
    printf ("mode:%03o, cbytes:%lu, qnum:%lu, qbytes:%lu\n", \
			info.msg_perm.mode & 0777, info.msg_cbytes,  \
			info.msg_qnum, info.msg_qbytes);

	return 0;
}

进程之间点对点通讯

client1

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

#define handle_error(msg) \
    {perror(msg);exit(EXIT_FAILURE);}

#define MSG_TYPE1 1
#define MSG_TYPE2 2

struct msgbuf
{
	long mtype;
	char mtext[80];
};

int main (int argc, char *argv[])
{
//	key_t key = ftok (".", 511);
	key_t key = 511;
	int msg_id = msgget (key, IPC_CREAT | 0666);
	struct msgbuf msg1, msg2;

	int ret_from_fork;
	ret_from_fork = fork ();
	if (ret_from_fork == -1)
        handle_error("fork")
	else if (ret_from_fork == 0)
	{
		while (1)
		{
			gets (msg1.mtext);
			msg1.mtype = MSG_TYPE1;
			msgsnd (msg_id, &msg1, 80, 0);
		}
	}
	else
	{
		while (1)
		{
			memset (&msg2, 0, sizeof(msg2));
			if (msgrcv (msg_id, (void *)&msg2, \
                        sizeof(msg2.mtext), MSG_TYPE2, 0) == -1)
			    handle_error("msgrcv");
            printf ("client2: %s\n", msg2.mtext);
		}
	}
	msgctl (msg_id, IPC_RMID, NULL);
	return 0;
}

client2

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

#define handle_error(msg) \
    {perror(msg);exit(EXIT_FAILURE);}

#define MSG_TYPE1 1
#define MSG_TYPE2 2

struct msgbuf
{
	long mtype;
	char mtext[80];
};

int main (void)
{
//	key_t key = ftok (".", 511);
	key_t key = 511;
	int msg_id = msgget (key, IPC_CREAT | 0666);
	struct msgbuf msg1, msg2;

	int ret_from_fork;
	ret_from_fork = fork ();
	if (ret_from_fork == -1)
        handle_error("fork")
	else if (ret_from_fork == 0)
	{
		while (1)
		{
			gets (msg2.mtext);
			msg2.mtype = MSG_TYPE2;
			msgsnd (msg_id, &msg2, 80, 0);
		}
	}
	else
	{
		while (1)
		{
			memset (&msg1, 0, sizeof(msg1));
			if (msgrcv(msg_id, (void *)&msg1, \
                       sizeof(msg1.mtext), MSG_TYPE1, 0) == -1)
			    handle_error("msgrcv");
            printf ("client1: %s\n", msg1.mtext);
		}
	}
	return 0;
}

多人聊天室

client

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

#define handle_error(msg) \
    {perror(msg);exit(EXIT_FAILURE);}

#define TO_SERVER_MSGTYPE 1000

struct msgbuf
{
	long mtype;
	int client_id;
	char mtext[80];
};

int main (void)
{
//	key_t key = ftok ("./", 512);
	key_t key = 512;
	int msg_id = msgget (key, IPC_CREAT | 0666);

	struct msgbuf msg_snd, msg_rcv;

	printf ("input guest ID:");
	int client_id;
	scanf ("%d", &client_id);
	printf ("client_id: %d\n", client_id);

	int ret_from_fork;
	ret_from_fork = fork ();
	if (ret_from_fork == -1)
        handle_error("fork")	
	else if (ret_from_fork == 0)
	{
		while (1)
		{
			gets (msg_snd.mtext);
			msg_snd.mtype = TO_SERVER_MSGTYPE;
			msg_snd.client_id = client_id;
			msgsnd (msg_id, &msg_snd, 80, 0);
		}
	}
	else
	{
		while (1)
		{
			memset (&msg_rcv, 0, sizeof(msg_rcv));
			if (msgrcv (msg_id, (void *)&msg_rcv, \
                        sizeof(msg_rcv.mtext), client_id, 0) == -1)
			    handle_error("msg_rcv")
			else
				printf ("client%d: %s\n", msg_rcv.client_id, msg_rcv.mtext);
		}
	}
	return 0;
}

server

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


#define TO_SERVER_MSGTYPE 1000
#define CLIENT_NUMBER 3

struct msgbuf
{
	long mtype;
	int client_id;
	char mtext[80];
};

int main (void)
{
//	key_t key = ftok ("./", 512);
	key_t key = 512;
	int msg_id = msgget (key, IPC_CREAT | 0666);
	struct msgbuf msg;

    while (1)
	{
	    memset (&msg, 0, sizeof(msg));
		if (msgrcv (msg_id, (void *)&msg, sizeof(msg.mtext), \
					TO_SERVER_MSGTYPE, 0) == -1)
		{
			perror ("msgrcv");
			exit (EXIT_FAILURE);
		}
		else
		{
			for (int i = 1; i <= CLIENT_NUMBER; i++)
			{
				if (i == msg.client_id)
					continue;
				else
				{
					msg.mtype = i;
					msgsnd (msg_id, &msg, 80, 0);
				}
			}
		}
		printf ("server: %s\n", msg.mtext);
	}
	msgctl (msg_id, IPC_RMID, NULL);
	return 0;
}

readme

usage:
	$ ./client
	$ input client ID :
	support >3 clients