如何使用管道在两个程序之间发送一个简单的字符串? [英] How to send a simple string between two programs using pipes?

问题描述

我尝试在网上搜索，但几乎没有任何资源.一个小例子就足够了.

I tried searching on the net, but there are hardly any resources. A small example would suffice.

编辑我的意思是，两个不同的 C 程序相互通信.一个程序应该发送Hi"，另一个程序应该接收它.类似的东西.

EDIT I mean, two different C programs communicating with each other. One program should send "Hi" and the other should receive it. Something like that.

推荐答案

一个普通的管道只能连接两个相关的进程.它是由一个进程创建的，当最后一个进程关闭它时它会消失.

A regular pipe can only connect two related processes. It is created by a process and will vanish when the last process closes it.

命名管道，因其行为也称为 FIFO, 可用于连接两个不相关的进程，独立于进程而存在；这意味着即使没有人使用它，它也可以存在.FIFO 是使用 mkfifo() 库函数.

A named pipe, also called a FIFO for its behavior, can be used to connect two unrelated processes and exists independently of the processes; meaning it can exist even if no one is using it. A FIFO is created using the mkfifo() library function.

writer.c

#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>

int main()
{
    int fd;
    char * myfifo = "/tmp/myfifo";

    /* create the FIFO (named pipe) */
    mkfifo(myfifo, 0666);

    /* write "Hi" to the FIFO */
    fd = open(myfifo, O_WRONLY);
    write(fd, "Hi", sizeof("Hi"));
    close(fd);

    /* remove the FIFO */
    unlink(myfifo);

    return 0;
}

reader.c

#include <fcntl.h>
#include <stdio.h>
#include <sys/stat.h>
#include <unistd.h>

#define MAX_BUF 1024

int main()
{
    int fd;
    char * myfifo = "/tmp/myfifo";
    char buf[MAX_BUF];

    /* open, read, and display the message from the FIFO */
    fd = open(myfifo, O_RDONLY);
    read(fd, buf, MAX_BUF);
    printf("Received: %s
", buf);
    close(fd);

    return 0;
}

_{注意:为简单起见，上面的代码省略了错误检查.}

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