Subroutine does not sleep

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

I call a subroutine suplying a variable and want the script to sleep for that amount of time. But it seems that the subroutine does not sleep (or at least only 1 second). Here is the script:

#!/usr/bin/perl -w
use strict;
 while () {
    my $wait = 6000;
    my $time_now= time;
    &wait ($wait);
    print time-$time_now,"\n";
 }
 
 sub wait{
    my $time =@_;
    sleep $time;
 }
[download]

The Output is

 
1
1
1
...
[download]

Any ideas how this poor subroutine can get some more sleep?

Comment on Subroutine does not sleep Select or Download Code

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Re: Subroutine does not sleep by hgolden (Pilgrim) on Oct 06, 2006 at 14:29 UTC
Hey You're calling the array in scalar context, so it's returning the number of elements in it (which is 1). Try using shift: `my $time=shift;` Hays	[reply] [d/l]
Re: Subroutine does not sleep by monkey_boy (Priest) on Oct 06, 2006 at 14:29 UTC
change `sub wait{ my $time =@_; sleep $time; }` [download] to `sub wait{ my ($time) =@_; sleep $time; }` [download] As in this scalar context $time is being set to the size of @_ (i.e. 1) instead of the value. This is not a Signature...	[reply] [d/l] [select]
Re: Subroutine does not sleep by davorg (Chancellor) on Oct 06, 2006 at 14:31 UTC
my $time =@_; You're evaluating the array, @_, in scalar context. So you get the number of elements. Try using this instead: `my ($time) = @_;` [download] -- <http://dave.org.uk> "The first rule of Perl club is you do not talk about Perl club." -- Chip Salzenberg	[reply] [d/l]
Re: Subroutine does not sleep by arkturuz (Curate) on Oct 06, 2006 at 14:34 UTC
In `wait` function read the parameter like: `my $time = shift` or `my ($time) = (@_)`. Also, there is a perl function `wait`. You should name your functions differently, to avoid clashes with builtins.	[reply] [d/l] [select]
Re: Subroutine does not sleep by kwaping (Priest) on Oct 06, 2006 at 14:54 UTC
Also, don't forget to turn on autoflush (`$\| = 1;` will do that). Otherwise, your perception of what the program is doing is going to be skewed by output buffering. Update: I re-read the thread and realized my reply doesn't address the issue. However, I feel it's still good general advice for something like this. --- It's all fine and dandy until someone has to look at the code.	[reply] [d/l]
Re^2: Subroutine does not sleep by Anonymous Monk on Oct 06, 2006 at 15:35 UTC
But the advice isn't that useful. He's printing to the terminal, and the terminal is in line-buffer mode. Regardless of the value of $\|, as soon as a newline is printed (which he does), the output gets flushed.	[reply]