程序未接收和发送备用
Programs Not Receiving and Sending Alternatively
程序似乎可以工作,但无法弄清楚为什么它不运行代码的第二部分。例如,当我编译并执行msg2时.cpp它会提示用户"输入一些文本"。当用户输入文本 msg1 时.cpp将显示用户输入。问题是 msg1.cpp 没有提示用户"输入一些文本"。关于如何以替代方式接收和发送消息的任何建议?
//msg2.cpp
/* The sender program is very similar to msg1.cpp. 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/types.h>
#include <sys/ipc.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];
long int msg_to_receive = 0;
msgid = msgget((key_t)1234, 0666 | IPC_CREAT);
if (msgid == -1) {
fprintf(stderr, "msgget failed with error: %dn", errno);
exit(EXIT_FAILURE);
}
while(running) {
printf("Enter some text: ");
fgets(buffer, BUFSIZ, stdin);
some_data.my_msg_type = 1;
strcpy(some_data.some_text, buffer);
if (msgsnd(msgid, (void *)&some_data, MAX_TEXT, 0) == -1) {
fprintf(stderr, "msgsnd failedn");
exit(EXIT_FAILURE);
}
if (strncmp(buffer, "end", 3) == 0) {
running = 0;
}
}
/* Then the messages are retrieved from the queue, until an end message is encountered.
Lastly, the message queue is deleted. */
while(running) {
if (msgrcv(msgid, (void *)&some_data, BUFSIZ,
msg_to_receive, 0) == -1) {
fprintf(stderr, "msgrcv failed with error: %dn", errno);
exit(EXIT_FAILURE);
}
printf("You wrote: %s", some_data.some_text);
if (strncmp(some_data.some_text, "end", 3) == 0) {
running = 0;
}
}
if (msgctl(msgid, IPC_RMID, 0) == -1) {
fprintf(stderr, "msgctl(IPC_RMID) failedn");
exit(EXIT_FAILURE);
}
exit(EXIT_SUCCESS);
}
//msg1.cpp
/* Here's the receiver program. */
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/msg.h>
#define MAX_TEXT 512
//string UserInput(string);
struct my_msg_st {
long int my_msg_type;
char some_text[BUFSIZ];
//char some_text[MAX_TEXT];
};
int main()
{
int running = 1;
int msgid;
struct my_msg_st some_data;
long int msg_to_receive = 0;
char buffer[BUFSIZ];
char some_text[MAX_TEXT];
//string input;
/* First, we set up the message queue. */
msgid = msgget((key_t)1234, 0666 | IPC_CREAT);
if (msgid == -1) {
fprintf(stderr, "msgget failed with error: %dn", 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 (msgrcv(msgid, (void *)&some_data, BUFSIZ,
msg_to_receive, 0) == -1) {
fprintf(stderr, "msgrcv failed with error: %dn", errno);
exit(EXIT_FAILURE);
}
printf("You wrote: %s", some_data.some_text);
if (strncmp(some_data.some_text, "end", 3) == 0) {
running = 0;
}
}
if (msgctl(msgid, IPC_RMID, 0) == -1) {
fprintf(stderr, "msgctl(IPC_RMID) failedn");
exit(EXIT_FAILURE);
}
// Need to reset value, before entering second loop
// At this point, value enters loop, prompts user enter text
while(running) {
printf("Enter some text: ");
for (int i = 1; i < running; i++){
fgets(buffer, BUFSIZ, stdin);
some_data.my_msg_type = 1;
strcpy(some_data.some_text, buffer);
}
if (msgsnd(msgid, (void *)&some_data, MAX_TEXT, 0) == -1) {
fprintf(stderr, "msgsnd failedn");
exit(EXIT_FAILURE);
}
if (strncmp(buffer, "end", 3) == 0) {
running = 0;
}
}
exit(EXIT_SUCCESS);
}
我的 .02 货币单位位于 msg1.cpp 的以下代码段上:
if (msgctl(msgid, IPC_RMID, 0) == -1) {
fprintf(stderr, "msgctl(IPC_RMID) failedn");
exit(EXIT_FAILURE);
}
您似乎在收到"结束"消息后立即在此处删除消息队列。
(另:fprintf()
和朋友在C++节目中?(
相关文章:
- Mongodb c++驱动程序:如何查询元素的数组
- C++,系统无法执行指定的程序
- 在C++程序中输入的文本文件将不起作用,除非文本被复制和粘贴
- 在VS代码中交叉编译Windows与Linux上的MinGW的SDL程序
- C++ Windows 驱动程序MSB3030无法复制该文件,因为它找不到
- 重载操作程序时出错>>用于类中的字符串 memebr
- 获取日期异步信号安全吗?如果在信号处理程序中使用,它会导致死锁吗
- 试图在visual studio上用C++创建一个桌面应用程序
- 模板元程序查找相似的连续类型名称
- FFmpeg:制作一个应用程序比直接使用ffmepg更好吗
- 如何通过cpp程序运行shell脚本
- 有没有什么方法可以使用一个函数中定义的常量变量,也可以由c++中同一程序中的其他函数使用
- IPC使用多个管道和分支进程来运行Python程序
- 如何将c++程序的一些输出传递给shell,以便在shell中使用
- 使用C++程序合并排序没有得到正确的输出
- 基于boost的程序的静态链接——zlib问题
- 程序崩溃并显示"std::out_of_range"错误
- 在C应用程序中运行C++(带有STL)函数
- 使用mongocxx驱动程序时包含头文件问题
- 程序未接收和发送备用