#!/usr/bin/perl
## Submitted by Borislav Deianov <borislav@users.sourceforge.net>
## This stresses the blocking write to see if it blocks.
use Fcntl;
use IO::Pty;
use IPC::Run qw(run);
sub makecmd {
    return [
        'perl', '-e',
        '<STDIN>, print "\n" x ' . $_[0] . '; while(<STDIN>){last if /end/}'
    ];
}
pipe R, W;
fcntl( W, F_SETFL, O_NONBLOCK );
while ( syswrite( W, "\n", 1 ) ) { $pipebuf++ }
print "pipe buffer size is $pipebuf\n";
$in = "\n" x ( $pipebuf * 3 ) . "end\n";
print "reading from scalar via pipe... ";
run( makecmd( $pipebuf * 3 ), '<', \$in, '>', \$out );
print "done\n";
print "reading from code via pipe... ";
run( makecmd( $pipebuf * 3 ), '<', sub { $t = $in; undef $in; $t }, '>', \$out );
print "done\n";
$pty = IO::Pty->new();
$pty->blocking(0);
$slave = $pty->slave();
while ( $pty->syswrite( "\n", 1 ) ) { $ptybuf++ }
print "pty buffer size is $ptybuf\n";
$in = "\n" x ( $ptybuf * 3 ) . "end\n";
print "reading via pty... ";
run( makecmd( $ptybuf * 3 ), '<pty<', \$in, '>', \$out );
print "done\n";