Re: Re: while (1==1) results in subroutine not called

So ya'll know, sometimes (like when I wrote car talk the other day) when I just breifly described a problem, someone imedatly came back with that the problem was or similar circumstances... Anyways, I attempted an approximate code snipet below...

for my $x (0..4){ # pesudo calling function
  system("(sleep 5); touch done_" . $x);
}
&wait(4);
sub wait{
  my $c = shift;
  my $i=0;
  while ($c != $i){ # If I make this $c==$i, returns no problem
    for my $j (0..$c){
      if (-e "done_" . $j){
        unlink "done_" . $j;
        $i++;
      }
    }
  }
}
[download]

Now there's nothing above which is screaming to me that the sub routine wait won't be called, but apparently it never is...

----
Zak

undef$/;$mmm="J\nutsu\nutss\nuts\nutst\nuts A\nutsn\nutso\nutst\nutsh\
+nutse\nutsr\nuts P\nutse\nutsr\nutsl\nuts H\nutsa\nutsc\nutsk\nutse\n
+utsr\nuts";open($DOH,"<",\$mmm);$_=$forbbiden=<$DOH>;s/\nuts//g;print
+;
[download]

Comment on Re: Re: while (1==1) results in subroutine not called Select or Download Code

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Re: while (1==1) results in subroutine not called by Abigail-II (Bishop) on Sep 30, 2003 at 20:52 UTC
Of course the while loop never terminates. You make five files, then call &wait (a name I would never have picked since wait is a keyword) with argument 4. In the loop, you delete 5 files, increasing $i with 1 for each file deleted. So, $i equals 5, $c equals 4. And 4 will never be 5. Abigail	[reply]
Re: Re: Re: while (1==1) results in subroutine not called by antirice (Priest) on Sep 30, 2003 at 20:42 UTC
Note that all the system calls don't return until what it runs has exited (thus why system returns the exit status of what was called). Also, you have a small counting problem. The array 0..4 contains 5 elements. All of this combines to create a situation where on the first iteration of the while, 4!=0 is tested and, since all the files were created earlier with the system calls, 4!=5 is tested each time thereafter. Perhaps testing for $c >= $i? Perhaps something like: `for my $x (0..4){ # pesudo calling function system("( sleep 5 ; touch done_$x ; ) &"); } &wait(4); sub wait{ my $c = shift; my $i=0; while ($c >= $i){ for my $j (0..$c){ if (-e "done_" . $j){ unlink "done_" . $j; $i++; } } } }` [download] Hope this helps. antirice The first rule of Perl club is - use Perl The ith rule of Perl club is - follow rule i - 1 for i > 1	[reply] [d/l]
Re: Re: Re: while (1==1) results in subroutine not called by hardburn (Abbot) on Sep 30, 2003 at 20:42 UTC
Step back from your code and figure out what the real problem you're trying to solve is. It appears that you just want your program to wait a while. Which is what sleep is for. Not the shell program, mind you--Perl has this functionality built in. ---- I wanted to explore how Perl's closures can be manipulated, and ended up creating an object system by accident. -- Schemer Note: All code is untested, unless otherwise stated	[reply]
Re: Re: Re: Re: while (1==1) results in subroutine not called by zakzebrowski (Curate) on Sep 30, 2003 at 20:48 UTC
The "sleep" program was just an example... What I want to do (and I forgot to put in the & ) was for a background programs to "do something". I want a notification to know when all of the programs have exited, so I can scp any output files back to the orignal host... (Which I have working, just not when I launch a bunch of background programs...) I'll figure it out.. ---- Zak `undef$/;$mmm="J\nutsu\nutss\nuts\nutst\nuts A\nutsn\nutso\nutst\nutsh\ +nutse\nutsr\nuts P\nutse\nutsr\nutsl\nuts H\nutsa\nutsc\nutsk\nutse\n +utsr\nuts";open($DOH,"<",\$mmm);$_=$forbbiden=<$DOH>;s/\nuts//g;print +;` [download]	[reply] [d/l]
Re: Re: Re: while (1==1) results in subroutine not called by eric256 (Parson) on Sep 30, 2003 at 20:42 UTC
I'm just shooting in the dark here but wouldn't... `for my $x (0..4){ # pesudo calling function system("(sleep 5); touch done_" . $x); } &wait(4); sub wait{ my $c = shift; for my $i (0..$c) { for my $j (0..$c){ if (-e "done_" . $j){ unlink "done_" . $j; } } } }` [download] Work just the same? I'm assuming that you have some use for deleteing the same files 4 times, but its unlcear from this. ___________ Eric Hodges	[reply] [d/l]


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