On Wed, 28 Aug 2002 07:30:15 -0500, [EMAIL PROTECTED] (Philip
Montgomery) wrote:
>I am trying to figure out how to run process concurrently from Perl. I want the
>parent to spawn off the children and wait until they are complete to continue. I can
>get the child processes to run in serial, but I need them to run in parallel.
>
>The code I am using thus far is
>
>for ($x;$x<4;$x++) {
> if ($pid=fork) {
> } else {
> system "mkdir dir$x";
> for ($i=1;$i<250;$i++) {
> open3(OUTPUT, INPUT, ERRORS, cd dir$x;make clean; make all);
> <code to process the output of the make commands and store into log files>
> }
>}
>
>Thanks for any help.
Here is something written by Abigail on perlmonks.org.
################################################################
#!/usr/bin/perl
=head1
Some times you have a need to fork of several children, but you want to
limit the maximum number of children that are alive at one time. Here
are two little subroutines that might help you, mfork and afork. They
are very similar.
They take three arguments,
and differ in the first argument. For mfork, the first
argument is a number, indicating how many children should be forked. For
afork, the first argument is an array - a child will be
forked for each array element. The second argument indicates the maximum
number of children that may be alive at one time. The third argument is
a code reference; this is the code that will be executed by the child.
One argument will be given to this code fragment; for mfork it will be
an increasing number,
starting at one. Each next child gets the next number. For afork, the
array element is
passed. Note that this code will assume no other children will be
spawned,
and that $SIG {CHLD} hasn't been set to IGNORE.
by Abigail
=cut
mfork (10,10,\&hello);
sub hello{print "hello world\n";}
###################################################
sub mfork ($$&) {
my ($count, $max, $code) = @_;
foreach my $c (1 .. $count) {
wait unless $c <= $max;
die "Fork failed: $!\n" unless defined (my $pid = fork);
exit $code -> ($c) unless $pid;
}
1 until -1 == wait;
}
##################################################
sub afork (\@$&) {
my ($data, $max, $code) = @_;
my $c = 0;
foreach my $data (@$data) {
wait unless ++ $c <= $max;
die "Fork failed: $!\n" unless defined (my $pid = fork);
exit $code -> ($data) unless $pid;
}
1 until -1 == wait;
}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
and here is an afork example
######################################################
#!/usr/bin/perl
=head1
For afork, the first argument is an array - a child will be
forked for each array element. The second argument indicates the maximum
number of children that may be alive at one time. The third argument is
a code reference; this is the code that will be executed by the child.
One argument will be given to this code fragment. For afork, the array
element ispassed. Note that this code will assume no other children will
be spawned,and that $SIG {CHLD} hasn't been set to IGNORE.
by Abigail
=cut
if ($#ARGV < 0){@ARGV = qw( 1 2 3 4 5)}
afork (\@ARGV,10,\&hello);
sub hello{print "hello world\n";}
##################################################
sub afork (\@$&) {
my ($data, $max, $code) = @_;
my $c = 0;
foreach my $data (@$data) {
wait unless ++ $c <= $max;
die "Fork failed: $!\n" unless defined (my $pid = fork);
exit $code -> ($data) unless $pid;
}
1 until -1 == wait;
}
#####################################################
--
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
