c - 送线其他多线程

Question

我看到使用 fork 在两个进程之间打开管道很容易，但是我们如何将打开的管道传递给线程。假设我们需要“可能通过多个线程”将 PROGRAM A 传递给 PROGRAM B，PROGRAM B 将其输出发送到 PROGRAM C

编辑：我在修改代码后又来了，变得更容易阅读。

#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <fcntl.h>

void *thread1(void *arg) {

    int status, fd[2];
    pid_t pid;

    pipe(fd);
    pid = fork();

    if (pid == 0) {
        int fd2 = *((int *) (arg));
        dup2(STDIN_FILENO, fd2);

        close(fd[0]);
        dup2(fd[1], STDOUT_FILENO);
        close(fd[1]);

        execvp("PROGRAM B", NULL);
        exit(1);
    } else {
        close(fd[1]);
        dup2(fd[0], STDIN_FILENO);
        close(fd[0]);

        execl("PROGRAM C", NULL);
        wait(&status);

        return NULL;
    }
}

int main(void) {


    FILE *fpipe;
    char *command = "PROGRAM A";
    char buffer[1024];

    if (!(fpipe = (FILE*) popen(command, "r"))) {
        perror("Problems with pipe");
        exit(1);
    }

    char* outfile = "out.dat";
    //FILE* f = fopen (outfile, "wb");
    //int fd = fileno( f );

    int fd[2];
    fd[0] = open(outfile, O_WRONLY);

    pthread_t thid;
    if (pthread_create(&thid, NULL, thread1, fd) != 0) {
        perror("pthread_create() error");
        exit(1);
    }

    int len;
    while (read(fpipe, buffer, sizeof (buffer)) != 0) {
        len = strlen(buffer);
        write(fd[0], buffer, len);
    }

    pclose(fpipe);

    return (0);
}

Answer 1

对于进程内消息传递，POSIX 队列可能比管道更适合您的需求。退房man mq_overview（或在线）。