Error

**bartz** · 10-11-2006

Originally Posted by SKeane

On a PC, Unix box?

Unix PC 64bit

**Happy_Reaper** · 10-11-2006

The difference is that a char is an area in memory (about 8 bits), that your compiler will dedicate to a character.

char*, instead, points to an area in memory that is supposed to contain a char. (Plus char* are more than 8bits I think).

**SKeane** · 10-11-2006

Presumably Linux? In which case

man 3 echo

look at int noecho() and int echo() functions.

**bartz** · 10-11-2006

FreeBSD

**SKeane** · 10-11-2006

The difference is that a char is an area in memory (about 8 bits), that your compiler will dedicate to a character.

Plus you are locally hiding the x in the outer scope, which is usually not a good thing. Why do you need a 'local' x in the loop?

**bartz** · 10-11-2006

Well, don't know why I needed that? I'm very new to C so it's hard working with the *'s and stuff.

Does anyone of you know how to hide things you type? It's for password stuff, so I want it to be printed as stars or not printed at all, is this possible?

**SKeane** · 10-11-2006

You have to turn off terminal echoing. Does FreeBSD not have a man page on echo?

**bartz** · 10-11-2006

I understand I should turn off terminal echoing, but I don't know how to do it in C... Can anyone help me?

**SKeane** · 10-12-2006

Did you do a man 3 echo?

**bartz** · 10-12-2006

Yes I did, but it doesn't work, I get a segmentation fault:

Code:

#include <curses.h>
#include <stdio.h>
#include <string.h>

int main (int argc, char **argv) {
  char *answer = malloc(64*1);
  noecho();
  printf ("Pass? ");
  scanf ("%s", &answer);
  return 0;
}

~/C$ gcc -o quiet -lcurses quiet.c
~/C$ ./quiet
Segmentation fault: 11 (core dumped)
~/C$

**SKeane** · 10-12-2006

Take the '&' off answer in the scanf().

Code:

scanf ("%s", answer);

**bartz** · 10-12-2006

Still the same error, it works fine when I delete the noecho() line...

**whiteflags** · 10-12-2006

> If I want to ask a password, how can I make sure it's printed as *'s or it isn't printed at all?
Not to insult or talk over Skeane, but the C FAQ item 19.1 goes into this with exhaustive detail. I suspect you are getting a segmentation fault because you're using the curses library without setting up a WINDOW.

**bartz** · 10-12-2006

Ok, thank you guys very much for your help

**SKeane** · 10-12-2006

If you want to continue in the vein you are ...

Code:

#include <curses.h>
#include <stdio.h>
#include <string.h>

int main (int argc, char **argv)
{
  char *answer = malloc(64*1);

  (void) initscr();
  (void) raw;
  (void) noecho();

  printw ("Pass? ");
  refresh();
  scanf ("%s", answer);
  (void) echo();
  endwin();

  printf("You entered %s\n", answer);

  return(0);
}

Otherwise follow citizen's advice.