管道读卡器看不到EOF或EOS

Question

在此函数中，如何进行此操作以便父级停止尝试从管道中读取。即如果我运行命令ls | grep test grep不会输出test和test.c然后等待用户输入？

pipe(pipefd);

int pid = fork();
if (pid != 0) {
    dup2(pipefd[0], STDIN_FILENO);
    int rv2 = execv(get_contain_dir(command_to), args_to);
    close(pipefd[0]);
} else {
    dup2(pipefd[1], STDOUT_FILENO);
    int rv1 = execv(get_contain_dir(command_from), args_from);
    close(pipefd[1]);
}

Answer 1

您没有正确关闭管道。每个进程都必须关闭它不使用的管道：

int pid = fork();
if (pid != 0) {
    dup2(pipefd[0], STDIN_FILENO);
    close(pipefd[1]); // not using the left side
    int rv2 = execv(get_contain_dir(command_to), args_to);

} else {
    dup2(pipefd[1], STDOUT_FILENO);
    close(pipefd[0]);  // not using the right side 
    int rv1 = execv(get_contain_dir(command_from), args_from);
}