Thread: Programming a Tiny More Binary

Hello,

I have an issue with scanf. I would like to press enter like "more" does.

Sorry if my programme is really for beginners and very basic.

Would you know about possibilities here to solve this?

Code:

// to compile: tcc nmore.c -o nmore


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


#include <sys/ioctl.h>
#include <unistd.h>
//printf ("lines %d\n", w.ws_row);
//printf ("columns %d\n", w.ws_col);






int main()
{


        char str[500];


        struct winsize w;
        ioctl(STDOUT_FILENO, TIOCGWINSZ, &w);
        double linemax= (double)(w.ws_row);
        double linepos = 0;
        double charpos=0 ; 


        int begin = 1;
        int c ; 
        c = getchar();
        while( c != EOF )
        {
           if ( begin == 1 ) 
           {
               if ( linepos >= linemax )  
               {
                     linepos = 0;
                     printf( "New Line\n" );
                     scanf("%[^\t\n]s",str);    // <-- this is not working
                     // press key
               }


               printf( "%.0f: ", charpos++);
               linepos++;
           }
           putchar( c );
           begin = 0;
           if ( c == '\n' ) begin = 1;
           c = getchar();
        }
	return 0;
 }

Originally Posted by spartrekus

Hello,

I have an issue with scanf. I would like to press enter like "more" does.

Sorry if my programme is really for beginners and very basic.

Would you know about possibilities here to solve this?

Code:

// to compile: tcc nmore.c -o nmore


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


#include <sys/ioctl.h>
#include <unistd.h>
//printf ("lines %d\n", w.ws_row);
//printf ("columns %d\n", w.ws_col);






int main()
{


        char str[500];


        struct winsize w;
        ioctl(STDOUT_FILENO, TIOCGWINSZ, &w);
        double linemax= (double)(w.ws_row);
        double linepos = 0;
        double charpos=0 ; 


        int begin = 1;
        int c ; 
        c = getchar();
        while( c != EOF )
        {
           if ( begin == 1 ) 
           {
               if ( linepos >= linemax )  
               {
                     linepos = 0;
                     printf( "New Line\n" );
                     scanf("%[^\t\n]s",str);    // <-- this is not working
                     // press key
               }


               printf( "%.0f: ", charpos++);
               linepos++;
           }
           putchar( c );
           begin = 0;
           if ( c == '\n' ) begin = 1;
           c = getchar();
        }
    return 0;
 }

The FAQ is huge.


Could you be specific on how to exit the input?

look, it is readily possible. It can be proved:
echo test | less
echo test | more


HELP

Originally Posted by userxbw

Maybe,
look at what your checking:

Code:

 double linemax= (double)(w.ws_row);double linepos = 0;
....
if (linepos >= linemax )

I don't fully understand it, but, reading more of your code even though it looks like it will meet that requirement in your if statement.

should it not check for an action instead?
if key press do something
mock code

Code:

while ( wait)
if ( action  == desired action / condition )
do it
else
wait for it

something like that perhaps?
or

Code:

while ( doing something && desired action / condition not reached)
{
   just keep on doing it, even if the doing something is just waiting. 
}

or

Code:

while ( doing something || until desired action / condition is reached)
{
just keep on doing it, even if the doing something is just waiting.
else
break;  on condition reached.
}

that last one look funny, don't trust it. until tried.
plus you're using a Pipe so you got to factor that in too. yes?

I am not so sure that you understood what does "more" or this "tiny more" applications. Probably you are using Windows, and haven't Unix background.

The pipe is use, but of course, keypress and pipe aren't compatible, as stated above.

Is there anyone having a possible idea or workaround?

thank you in advance !!

Originally Posted by GReaper

Simply put, in Unix systems you need to switch the buffering mode, get your input and then switch it back. This FAQ page provides a possible solution at the bottom.
FAQ > How do I get my program to wait for a keypress? - Cprogramming.com

i tried in this way, but without success, according to above.

here it seems, that there is no single way to interrupt stdin for scanf ...
c - How to interrupt standard input stream for another - Stack Overflow

Originally Posted by spartrekus

i tried in this way, but without success, according to above.

here it seems, that there is no single way to interrupt stdin for scanf ...
c - How to interrupt standard input stream for another - Stack Overflow

Tada !!!

Ok, I got it!


I have here made a project for it.
nmore/nmore.c at master * spartrekus/nmore * GitHub

Howto:

Code:

gcc nmore.c -o nmore ;  cat nmore.c | ./nmore

The little problem is that the |NMORE| line is still displayed. How to delete it ???
(idea of getting the whole buffer, and delete last line, and bring that again, but it is far too complex).