NAME

SYNOPSIS

        open my $in,  '< :flock', $file; # shared lock
        open my $out, '+<:flock', $file; # exclusive lock

        binmode($fh, ':flock(blocking)');
        binmode($fh, ':flock(non-blocking)');

DESCRIPTION

It tries to lock the filehandle with "flock()" according to the open mode. That is, if a file is opened for writing, ":flock" attempts exclusive lock (using LOCK_EX). Otherwise, it attempts shared lock (using LOCK_SH).

It waits until the lock is granted. If an argument "non-blocking" (or "LOCK_NB") is supplied, the call of "open()" (or "binmode()") fails when the lock cannot be granted.

This is a pseudo layer that doesn't be pushed on the layer stack.

EXAMPLE

        # tries shared lock, or waits until the lock is granted
        open my $in, "<:flock", $file;
        open my $in, "<:flock(blocking)", $file;     # ditto.

        # tries shared lock, or returns undef
        open my $in, "<:flock(non-blocking)", $file; 
        open my $in, "<:flock(LOCK_NB)", $file;      # ditto.

SEE ALSO

"flock" in perlfunc.

AUTHOR

LICENSE AND COPYRIGHT

This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself.