playingwithbots has asked for the wisdom of the Perl Monks concerning the following question:

I was trying to write some code to do some cursor control and wanted to read single characters. I've tried everything but Win32::Console seems not to work. I'm using ActiveState 5.8.0/806. Here is the code that I think should work. It should read characters and echo "*" characters as each is read. What happens is that I enter characters and get no echo and also get no "*" until I hit "enter". I then get the "*"'s echo'ed and it has read what I entered. 

use Win32::Console ;

$cons = new Win32::Console(STD_INPUT_HANDLE) || die "Can't open new co
+nsole\n";
$oldMode = $cons->Mode ;
$cons->Mode(~(ENABLE_LINE_INPUT|ENABLE_ECHO_INPUT) & $oldMode );
while (1) {
$char = $cons->InputChar(1) ;
last if ord $char == 13 ;
print '*' ;
$password .= $char ;
}
print "\nPassword was $password\n" ;
$cons->Mode($oldMode) ;

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Any help is appreciated.

Replies are listed 'Best First'.
Re: Win32::Console Modes not Working on XP
by BrowserUk (Patriarch) on Jul 18, 2003 at 20:06 UTC

    Disabling buffering on STDOUT seems to do the trick. Using strict and lexicals does hurt either. 

    #! perl -sw
use strict;
use Win32::Console ;

$|++; # Disable buffering on STDOUT.

my $password;

my $cons = new Win32::Console(STD_INPUT_HANDLE) || die "Can't open new
+ console\n";
my $oldMode = $cons->Mode ;
$cons->Mode(~(ENABLE_LINE_INPUT|ENABLE_ECHO_INPUT) & $oldMode );
while (1) {
    my $char = $cons->InputChar(1) ;
    last if ord $char == 13 ;
    print '*' ;
    $password .= $char ;
}
print "\nPassword was $password\n" ;
$cons->Mode($oldMode) ;
__END__
P:\test>junk
****
Password was fred

    [download]
    Examine what is said, not who speaks.
    "Efficiency is intelligent laziness." -David Dunham
    "When I'm working on a problem, I never think about beauty. I think only how to solve the problem. But when I have finished, if the solution is not beautiful, I know it is wrong." -Richard Buckminster Fuller
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Re: Win32::Console Modes not Working on XP
by NetWallah (Canon) on Jul 18, 2003 at 21:43 UTC
    In addition to BrowserUK's suggestion of $|++; # Disable buffering on STDOUT. , the order of the mode change seems significant.

    This works: 

    use Win32::Console ;

$cons = new Win32::Console(STD_INPUT_HANDLE) || die "Can't open new co
+nsole\n";
$|++; # Disable buffering on STDOUT.


ConsoleMode_AND_WITH (~(ENABLE_ECHO_INPUT));# 
ConsoleMode_AND_WITH ( ~(ENABLE_LINE_INPUT));#   
 
while (1) {
    $char = $cons->InputChar(1) ;
    last if ord $char == 13 ;
    print '*' ;
    $password .= $char ;
}
print "\nPassword was $password\n" ;
$cons->Mode($oldMode) ;

sub ConsoleMode_AND_WITH(){
  my $o = $cons->Mode();
  $cons->Mode($o & shift);  
  print "--Mode change from $o\[" . unpack(q(H2),chr($o)) . " ]  to  "
     . $cons->Mode() . "[". unpack(q(H2),chr($cons->Mode())) . "]\n";
}

    [download]
    Changing the order of ConsoleMode_AND_WITH calls produces the "Requires ENTER key" behaviour before anything shows up.

    MS documentation says ENABLE_LINE_INPUT OFF should ignore the setting of ENABLE_ECHO_INPUT. But this is probably getting off-topic. Anyway, the code above does what you require, as does Browser's.

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