接收者1：按顺序接收
/* Here's the receiver program. */
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <sys/msg.h>
struct my_msg_st {
long int my_msg_type;
char some_text[BUFSIZ];
};
int main()
{
int running = 1;
int msgid;
struct my_msg_st some_data;
long int msg_to_receive = 0;
int receivedata = 0;
/* First, we set up the message queue. */
printf("Enter some text: %d \n",BUFSIZ);
msgid = msgget((key_t)1234, 0666 | IPC_CREAT);
if (msgid == -1) {
fprintf(stderr, "msgget failed with error: %d\n", errno);
exit(EXIT_FAILURE);
}
/* Then the messages are retrieved from the queue, until an end message is encountered.
Lastly, the message queue is deleted. */
while(running) {
if ((receivedata = msgrcv(msgid, (void *)&some_data, BUFSIZ,
msg_to_receive, 0)) == -1) {
fprintf(stderr, "msgrcv failed with error: %d\n", errno);
exit(EXIT_FAILURE);
}
printf("You wrote: %s data length:%d \n", some_data.some_text,receivedata);
if (strncmp(some_data.some_text, "end", 3) == 0) {
running = 0;
}
}
#if 0
if (msgctl(msgid, IPC_RMID, 0) == -1) {
fprintf(stderr, "msgctl(IPC_RMID) failed\n");
exit(EXIT_FAILURE);
}
#endif
exit(EXIT_SUCCESS);
}
接收者2：接收特定类型
/* Here's the receiver program. */
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <sys/msg.h>
struct my_msg_st {
long int my_msg_type;
char some_text[BUFSIZ];
};
int main()
{
int running = 1;
int msgid;
struct my_msg_st some_data;
long int msg_to_receive = 1;
int receivedata = 0;
/* First, we set up the message queue. */
printf("Enter some text: %d \n",BUFSIZ);
msgid = msgget((key_t)1234, 0666 | IPC_CREAT);
if (msgid == -1) {
fprintf(stderr, "msgget failed with error: %d\n", errno);
exit(EXIT_FAILURE);
}
/* Then the messages are retrieved from the queue, until an end message is encountered.
Lastly, the message queue is deleted. */
while(running) {
if ((receivedata = msgrcv(msgid, (void *)&some_data, BUFSIZ,
msg_to_receive, 0)) == -1) {
fprintf(stderr, "msgrcv failed with error: %d\n", errno);
exit(EXIT_FAILURE);
}
printf("You wrote: %s data length:%d \n", some_data.some_text,receivedata);
if (strncmp(some_data.some_text, "end", 3) == 0) {
running = 0;
}
}
#if 0
if (msgctl(msgid, IPC_RMID, 0) == -1) {
fprintf(stderr, "msgctl(IPC_RMID) failed\n");
exit(EXIT_FAILURE);
}
#endif
exit(EXIT_SUCCESS);
}
发送者：
/* The sender program is very similar to msg1.c. In the main set up, delete the
msg_to_receive declaration and replace it with buffer[BUFSIZ], remove the message
queue delete and make the following changes to the running loop.
We now have a call to msgsnd to send the entered text to the queue. */
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <sys/msg.h>
#define MAX_TEXT 512
struct my_msg_st {
long int my_msg_type;
char some_text[MAX_TEXT];
};
int main()
{
int running = 1;
struct my_msg_st some_data;
int msgid;
char buffer[BUFSIZ];
msgid = msgget((key_t)1234, 0666 | IPC_CREAT);
if (msgid == -1) {
fprintf(stderr, "msgget failed with error: %d\n", errno);
exit(EXIT_FAILURE);
}
while(running) {
printf("Enter some text: %d \n",BUFSIZ);
fgets(buffer, BUFSIZ, stdin);
some_data.my_msg_type = 1;//改变发送类型
strcpy(some_data.some_text, buffer);
if (msgsnd(msgid, (void *)&some_data, MAX_TEXT, 0) == -1) {
fprintf(stderr, "msgsnd failed\n");
exit(EXIT_FAILURE);
}
if (strncmp(buffer, "end", 3) == 0) {
running = 0;
}
}
exit(EXIT_SUCCESS);
}
1.接收者可按照特定类型的消息接收，也可按照顺序接收。
2.发送者发送特定类型的消息
3.发送者和接收者不需要进程自己提供同步方法
来源：CSDN
作者：greatwall_2012
链接：https://blog.csdn.net/u011230664/article/details/104443476