Buffering is on by default. Try perl -e"print 'foo'; sleep 5; print 'bar'"

please note at line 26 I just typed return !?!

Reading from STDIN is documented to flush STDOUT. (One or both may need to be associated with a terminal for that to occur.)

Sure, turning on AUTOFLUSH helps!

  DB<1> $| = 1
 
  DB<2> x print "horst"
horst0  1
  DB<3> p print "horst"
horst1
  DB<4>  print "horst"
horst
[download]

But it's strange that only x doesn't flush automatically while other commands do ...

  DB<5> $| = 0
 
  DB<6> x print "horst"
0  1
  DB<7>  print "horst"
horsthorst
  DB<8> p print "horst"
1horst
[download]

Cheers Rolf

But it's strange that only x doesn't flush automatically

Not any stranger than using x and print together. I'm not terribly surprised that this particular combination was not "expected". In any case, the code in question is:

            # Turn off the one-time-dump stuff now.
            if ($onetimeDump) {
                $onetimeDump      = undef;
                $onetimedumpDepth = undef;
            }
            elsif ( $term_pid == $$ ) {
                eval {          # May run under miniperl, when not ava
+ilable...
                    STDOUT->flush();
                    STDERR->flush();
                };

                # XXX If this is the master pid, print a newline.
                print $OUT "\n";
            }
[download]

- tye