如何使用 c++ 制作终端仿真器并在 ncurses window 中显示 output？

Question

#include "Terminal.h"


void Terminal::send_buffer_to_terminal(std::string buffer)
{
    input << buffer << std::endl;
    input << "echo " << delimiter << std::endl;
}

std::string Terminal::terminal_process(std::string command)
{
    bp::child p("/bin/bash", std::vector<std::string>(), bp::std_out > output, bp::std_in < input);  
    while(1)
    {
        command.clear();
        //get_input(command);
        //printw("Enter command")
        send_buffer_to_terminal(command);
        std::cout << command ;
        process_command(command, output, input, delimiter);
        //_terminal_display._input_buffer.erase();
        //_terminal_display._enter = true;
    }
    // p.terminate();
    p.wait();
}

void Terminal::process_command(std::string& command, bp::ipstream& output, bp::opstream& input, char delimiter) {
    if(command == "exit")
    {
        return;
    }
    //input << command <<std::endl;
    //input << "echo "<< delimiter<<std::endl;

    std::string line;
    std::getline(output, line, delimiter);
    _terminal_display.add_message(line);
    // refresh();
    char c = output.get();
    assert(c == '\n');
}

This is the code i have. now i have another function from which i have to call the active window which is the terminal window and here is the code for it:

void DisplayManager::run()
{
    while(true)
    {
        
        move(LINES-2, 2);
        getstr(_input);
        if(strcmp(_input, "EXIT")==0)
        {
            break;
        }
        
        if(strcmp(_input, "SWITCH")==0)
        {
            _active_window = _active_window == CHAT_WINDOW ? TERM_WINDOW : CHAT_WINDOW;
            move(LINES-2, 0);
            clrtoeol();
            continue;
        }
        if(_active_window == CHAT_WINDOW)
        {
            add_chat_message(_input);    
        }
        else if(_active_window == TERM_WINDOW)
        {
            while(1)
            {
            getstr(_input);
            mvwprintw(_term_display._window, 1, 2, "i");
            _terminal.terminal_process(_input);
            }
        }
        move(LINES-2, 0);
        clrtoeol();
        display();
    }   
}

so i need to make the boost child run throughout the time i am using term_window. any idea how i could make this work?

I tried the terminal code and it works individually, but somehow i cannot display it in the terminal ncurses window and it is throwing boost::process::error, what() execve failed:Bad address error whenever i enter a shell command.

what i actually want to happen is that when i enter bash commands, i need it to execute the commands and display the result in ncurses window. btw, this is linux based.

Answer 1

You need to start a terminal emulator, for example with libvterm .

Then, the easiest way is to use forkpty instead of fork which correctly does openpty , fork and login_tty steps required to connect the child process to your terminal emulation.

In the child process make sure the TERM environment variable is set to the appropriate value.

In the parent process, until the child process exits, you need to

• Have async loops to process input/output between vt and pty master. This amounts to just reading whatever your receive, and pushing it to the terminal emulator ( libvterm has vterm_push_bytes for that purpose).
• Idem to process vt input ( vterm_output_get_buffer_current in libvterm ).

As an example (not using Asio) I got https://github.com/cantora/ncte to build and run on my box. That could be a starting point.

Out-Of-The-Box

If you're ready to start processes anyways, you should consider whether just launching an existing terminal emulator like xterm or gnome-terminal to run your child process in would not be a lot more straightforward