bug#19643: Emacs shell mode problem

[Eli Zaretskii <eliz@gnu.org>]

> From: <twilliam@twilliam.org>
> Date: Sat, 24 Jan 2015 09:45:03 -0700
> 
> Here is a simple one called oneline.pl:
> 
> use 5.012;
> use strict;
> #$|=1;
> 
> my $line = <STDIN>;
> print "\$line = $line\n";
> 
> In a DOS window it runs like this:
> 
> C:\Perl>oneline.pl
> 1234
> $line = 1234
> 
> C:\Perl>
> 
> Note in DOS I type in the line 1234, and the program prints "$line = 1234".
> 
> In Emacs shell mode it runs like this:
> 
> c:\Perl>oneline.pl
> oneline.pl
> $line = 
> 
> c:\Perl>
> 
> In Emacs the program doesn't pause to wait for a keyboard input. It blows right
> through it and then prints "$line = ".

I see this on Windows XP, but not on Windows 7.

So it's clearly some subtlety of how Windows buffers pipes and reads
from stdin.  Unless someone has more insight, I don't see what we can
do with this problem.