how to call exec multi-times...

[Jianli Shen]

Hi,

I write the following script,
hope it call "atouRcv -b ***** & " in each iteration.
however, it only call once when $port=6811

is that because: exec will not call the END block, nor will it call any
DESTROY method in the object ???

how can I make this loop work ??

Thanks


#!/usr/bin/perl

my $port=6811;
foreach my $r ( 0, 50, 200 ){
foreach my $l (0, 0.01, 0.05){
for (my $i=0; $i<=9; $i++) { #each run 10times
exec "atouRcv -b 2000000 -r ". $r . " -l ". $l . " -p " . $port . " &
";
$port += 1;
}
}
}

 

[A. Sinan Unur]

is that because: exec will not call the END block, nor will it call
any DESTROY method in the object ???

perldoc -f exec

exec LIST
exec PROGRAM LIST
The "exec" function executes a system command *and never
returns* ...

Read the documentation for more information.

Have you seen the posting guidelines for this group?

Sinan

 

[Jianli Shen]

Yes, I have read the perldoc,

is that put all the command to a command list then call exec ??

Thanks

 

[Jürgen Exner]

I write the following script,
hope it call "atouRcv -b ***** & " in each iteration.

How would that be? The program that is started via "exec" _replaces_ your
Perl program.
After calling exec once there is nothing left that could possibly iterate
anything.

however, it only call once when $port=6811

Yeah, that's the documented behaviour of exec().

is that because: exec will not call the END block, nor will it call
any DESTROY method in the object ???

No, it is because a successful exec() never returns to begin with.

how can I make this loop work ??

Use the proper tool. Maybe you were looking for system() instead?

jue

 

[John W. Krahn]

I write the following script,
hope it call "atouRcv -b ***** & " in each iteration.
however, it only call once when $port=6811

is that because: exec will not call the END block, nor will it call any
DESTROY method in the object ???

how can I make this loop work ??


#!/usr/bin/perl

my $port=6811;
foreach my $r ( 0, 50, 200 ){
foreach my $l (0, 0.01, 0.05){
for (my $i=0; $i<=9; $i++) { #each run 10times
exec "atouRcv -b 2000000 -r ". $r . " -l ". $l . " -p " . $port . " &
";
$port += 1;
}
}
}

Perhaps you want something like (UNTESTED):

#!/usr/bin/perl
use warnings;
use strict;

my $port = 6811;
for my $r ( 0, 50, 200 ) {
for my $l ( 0, 0.01, 0.05 ) {
for ( 1 .. 10 ) { # each run 10 times
defined( my $pid = fork ) or die "Cannot fork: $!";
$pid or exec 'atouRcv', '-b', 2000000, '-r', $r, '-l', $l, '-p', $port;
$port++;
}
}
}



John