设置行缓冲函数

#include <termios.h>
static struct termios oldt;
void restore_terminal_settings(void){
    // Apply saved settings
    tcsetattr(0, TCSANOW, &oldt);
}

void disable_terminal_settings(void){
    struct termios newt;
    //save terminal settings
    tcgetattr(0, &oldt);
    //init new settings
    newt = oldt;
    //change settings
    newt.c_lflag &= ~(ICANON | ECHO);
    //apply settings
    tcsetattr(0, TCSANOW, &newt);
    //make sure settings will be restored when program ends
    //atexit(restore_terminal_settings);
}

void return_terminal_settings(void){
    struct termios newt;
    //save terminal settings
    tcgetattr(0, &oldt);
    //init new settings
    newt = oldt;
    //change settings
    newt.c_lflag |= (ICANON | ECHO);
    //apply settings
    tcsetattr(0, TCSANOW, &newt);
}