Yet antoher keyboard/graphics question

[Poincare]

I know that with only C, you cannot interface with the keyboard or monitor but you can with assembly. I was wondering if just to recieve input from the say the keyboard (not parse it or anything, just recieve)would 300+ lines of code or was it easier than that? If it is a reasonable amount, then can someone post the code or direct me toward a link?

[Salem]

> I know that with only C, you cannot interface with the keyboard or monitor but you can with assembly
What's that supposed to mean?
Sure you can do those things in C, just not ANSI-C.

How close you can get to the keyboard depends on your OS.

You need to say more about your OS and Compiler for a more complete answer.

[Adak]

I know that with only C, you cannot interface with the keyboard or monitor but you can with assembly. I was wondering if just to recieve input from the say the keyboard (not parse it or anything, just recieve)would 300+ lines of code or was it easier than that? If it is a reasonable amount, then can someone post the code or direct me toward a link?

You can use C, and you should use C. You just can't use *PURE as the driven snow*, standard C.

Just find a compiler that includes (or can be arm-twisted), into using kbhit(). I use legacy Borland Turbo C/C++ ver. 1.01 for this, (using just the C compiler, not the C++ compiler), but a library like Ncurses may handle it, as well as other compilers.

/*
kbhit   Checks for currently-available keystrokes.

 Syntax:
   int kbhit(void);

 Prototype in:
 conio.h

 Remarks:
kbhit checks to see if a keystroke is currently available.

Any available keystrokes can be retrieved with getch or getche.

 Return Value:
If a keystroke is available, kbhit returns a nonzero integer; if not, it
returns 0.

 Portability:
kbhit is unique to DOS. (Works fine in Windows XP, however)

 See Also:
  getch    getche

 Example:
*/
#include <conio.h>
#include <stdio.h>

 int main(void)
 {
    int key1;
    cprintf("Press any key to continue:");
    while (!kbhit()) /* do nothing */ ;

    //getchar() (below) is standard C. getch() is part of the 
    //non-standard (but useful), conio.h
    key1 = getch();      //get a letter, w/o an enter key being needed

    //print the int that was pressed, as a letter
    printf("\r\nA key was pressed: %c", key1);

    //print the same int as it's ascii int value
    printf("\r\nA key was pressed: %d", key1);

    printf("\n\t\t\t     Press Enter When Ready ");
    key1 = getchar();   //pause the screen from closing
    
    return 0;
 }

[Poincare]

OS: Windows/Linux (whichever's easier)

Compiler: GCC

[MK27]

OS: Windows/Linux (whichever's easier)

Compiler: GCC

It really depends heavily on what you want to do.

In linux:

If you just want to have a program that deals with keyboard input in more dynamic way, there's ncurses and/or readline. I think that will solve most real "goal oriented" issues.

If you have something more technical in mind, well, the keyboard is controlled by the kernel via a module, which is open source and written in C. You could hack that or create a customized one. If you are interested in tooling around with/programming the hardware on a low level, kernel space is where you want to work methinks. The learning curve for the kernel API is a Pretty Challenging at first, and most normal C libs (eg, stdio.h) are not available.

[Salem]

FAQ maybe?
Cprogramming.com FAQ > How can I get input without having the user hit [Enter]?

[Poincare]

Thanks a lot! Seems like what I want to learn about is hidden in the kernel, which, sadly, I'm not elite enough to understand.