关于tputs()的用法

gulang2004xy

函数原型：tputs(char *const str, int affcnt, int (*putfunc)(int))
这个是设置终端输出显示参数设置的。看到了一段代码，不明白。例如int (*putfunc)(int)这个参数的作用是什么？int affcnt一般都设为1，
用来表示作用行数，下面的程序中tputs(clear, 1, char_to_terminal);这一句中设为1，但是清除的却是好几行，怎么回事？

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <termios.h>
#include <term.h>
#include <curses.h>

static FILE *output_stream = (FILE *)0;

char *menu[] = {
    "a - add new record",
    "d - delete record",
    "q - quit",
    NULL,
};

int getchoice(char *greet, char *choices[], FILE *in, FILE *out);
int char_to_terminal(int char_to_write);

int main()
{
    int choice = 0;
    FILE *input;
    FILE *output;
    struct termios initial_settings, new_settings;

    if (!isatty(fileno(stdout))) {
        fprintf(stderr,"You are not a terminal, OK.\n");
    }

    input = fopen("/dev/tty", "r");
    output = fopen("/dev/tty", "w");
    if(!input || !output) {
        fprintf(stderr, "Unable to open /dev/tty\n");
        exit(1);
    }
    tcgetattr(fileno(input),&initial_settings);
    new_settings = initial_settings;
    new_settings.c_lflag &= ~ICANON;
    new_settings.c_lflag &= ~ECHO;
    new_settings.c_cc[VMIN] = 1;
    new_settings.c_cc[VTIME] = 0;
    new_settings.c_lflag &= ~ISIG;
    if(tcsetattr(fileno(input), TCSANOW, &new_settings) != 0) {
        fprintf(stderr,"could not set attributes\n");
    }

    do {
        choice = getchoice("Please select an action", menu, input, output);
        printf("You have chosen: %c\n", choice);
        sleep(1);
    } while (choice != 'q');

    tcsetattr(fileno(input),TCSANOW,&initial_settings);
    exit(0);
}

int getchoice(char *greet, char *choices[], FILE *in, FILE *out)
{
    int chosen = 0;
    int selected;
    int screenrow, screencol = 10;

    char **option;
    char *cursor, *clear;

    output_stream = out;

    setupterm(NULL,fileno(out), (int *)0);
    cursor = tigetstr("cup");
    clear = tigetstr("clear");

    screenrow = 4;
    tputs(clear, 1, char_to_terminal);
    tputs(tparm(cursor, screenrow, screencol), 1, char_to_terminal);
    fprintf(out, "Choice: %s", greet);
    screenrow += 2;
    option = choices;        
    while(*option) {
        tputs(tparm(cursor, screenrow, screencol), 1, char_to_terminal);
        fprintf(out,"%s", *option);
        screenrow++;
        option++;
    }
    fprintf(out, "\n");

    do {
        fflush(out);
        selected = fgetc(in);
        option = choices;
        while(*option) {
            if(selected == *option[0]) {
                chosen = 1;
                break;
            }
            option++;
        }
        if(!chosen) {
            tputs(tparm(cursor, screenrow, screencol), 1, char_to_terminal);
            fprintf(out,"Incorrect choice, select again\n");
        }
    } while(!chosen);
    tputs(clear, 1, char_to_terminal);
    return selected;
}

int char_to_terminal(int char_to_write)
{
    if (output_stream) putc(char_to_write, output_stream);
    return 0;
}

crazyhadoop

那是回调函数，事件发生时调用别的函数来处理问题，  你的char_to_terminal 就是 实际被调用的函数，用来清理的， 清理的行数，由你设置的，  tparm(cursor, screenrow, screencol)  这个是设置吗？ 是清理了 4行吧。