How can I make Perl wait for child processes started in the background with system()?

Question

I have some Perl code that executes a shell script for multiple parameters, to simplify, I'll just assume that I have code that looks like this:

for $p (@a){
    system("/path/to/file.sh $p&");
}

I'd like to do some more things after that, but I can't find a way to wait for all the child processes to finish before continuing.

Converting the code to use fork() would be difficult. Isn't there an easier way?

Answer 1

Using fork/exec/wait isn't so bad:

my @a = (1, 2, 3);
for my $p (@a) {
   my $pid = fork();
   if ($pid == -1) {
       die;
   } elsif ($pid == 0) {
      exec '/bin/sleep', $p or die;
   }
}
while (wait() != -1) {}
print "Done\n";