Thanks Ray, and everyone else who answered, my script is working fine now,
got a few new tips in perl too.
Dan.
On Thu, 27 Jul 2000, Ray Olszewski wrote:
> Output to STDOUT is buffered. In perl, a LF forces the buffer to clear, so
> it prints immediately. That's why the third version works the way it does.
>
> The buffer also outputs when it gets full. That's why the first one does
> what it does; it is printing fast enough to fill the buffer quickly.
>
> Your second program is just enormously slow ... if you let it sit for
> (maybe) 15 minutes, you should see some output, whenever it gets around to
> filling the buffer.
>
> There is a switch in perl for unbuffered output (well, sort of unbuffered).
> Try putting the line "$| = 1 ; " before you start ptinting and see if that
> changes the way number two operates.
>
> This same behavior is often a problem in CGI programs written in perl.
>
> At 03:03 PM 7/27/00 +0000, Dan wrote:
> >Here's one that's driving me mad ... I'm trying to write a script and I want
> >the output to continue on the same line, but when I add in anything that
> >slows down the loop I can only get an output if I add a line feed.
> >
> >(RH 6.1 and perl-5.00503-6.)
> >
> >Any ideas?
> >
> >Dan.
> >
> >Three example are below to try and explain what I mean.
> >
> >-----------------------------------------------------------------------------
> >
> >#!/usr/bin/perl
> >
> >while () {
> > print "hello world";
> >}
> >
> >gives
> >
> >o worldhello worldhello worldhello worldhello worldhello worldhello
> >worldhello worldhello worldhello worldhello worldhello worldhello worldhello
> >worldhello worldhello worldhello worldhello worldhello worldhello worldhello
> >worldhello worldhello worldhello worldhello worldhello wor
> >
> >------------------------------------------------------------------------------
> >
> >When I add something in that slows the loop down, a subroutine, or even a
> >simple sleep command ...
> >
> >#!/usr/bin/perl
> >
> >while () {
> > print "hello world";
> > sleep 1;
> >}
> >
> >I get nothing at all, the cursor just sits there.
> >
> >------------------------------------------------------------------------------
> >
> >Then I add a line feed ...
> >
> >#!/usr/bin/perl
> >
> >while () {
> > print "hello world\n";
> > sleep 1;
> >}
> >
> >And get this ...
> >
> >hello world
> >hello world
> >hello world
> >hello world
> >hello world
> >hello world
> >hello world
> >hello world
>
>
> --
> ------------------------------------"Never tell me the odds!"---
> Ray Olszewski -- Han Solo
> Palo Alto, CA [EMAIL PROTECTED]
> ----------------------------------------------------------------
>
>
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