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Re^3: "open" Best Practices

by marioroy (Vicar)
on Jul 14, 2019 at 16:39 UTC ( #11102835=note: print w/replies, xml ) Need Help??


in reply to Re^2: "open" Best Practices
in thread "open" Best Practices

Hi karlgoethebier,

The mce_open call behaves similarly to the native open in Perl. It creates a shared handle with exclusive locking handled transparently.

Example:

use strict; use warnings; use feature 'say'; use MCE::Hobo; use MCE::Shared; # Passing a file ref without IO::FDPass will work for \*STDIN, # \*STDOUT, \*STDERR, and \*main::DATA only. Otherwise, providing # the actual path is preferred (i.e. "/path/to/file"). mce_open my $out, '>>', \*STDOUT or die 'open failed: $!'; mce_open my $err, '>>', \*STDERR or die 'open failed: $!'; printf $out "shared fileno(\$out) is %d\n", fileno($out); printf $out "shared fileno(\$err) is %d\n", fileno($err); if ($^O ne 'MSWin32') { mce_open my $log, '>>', '/dev/null' or die 'open failed: $!'; say $log "Hello, there!"; # sent to null } # The shared-handles work with threads, MCE::Hobo, MCE::Child, # Parallel::ForkManager, and other parallel modules on CPAN. # Note: There is no reason to choose MCE::Child over MCE::Hobo # if already involving the shared-manager. sub foo { my ($id) = @_; say $out "Hello, from pid $$"; } MCE::Hobo->create('foo', $_) for 1..4; MCE::Hobo->wait_all;

Output:

shared fileno($out) is 1 shared fileno($err) is 2 Hello, from pid 4651 Hello, from pid 4652 Hello, from pid 4653 Hello, from pid 4654

See also:

https://metacpan.org/pod/MCE::Shared#DBM-SHARING
https://metacpan.org/pod/MCE::Shared#LOGGER-DEMONSTRATION

Regards, Mario

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