NAME

       MCE::Signal - Temporary directory creation/cleanup and signal handling

VERSION

       This document describes MCE::Signal version 1.608

SYNOPSIS

        use MCE::Signal qw( [-keep_tmp_dir] [-use_dev_shm] );

        use MCE;   ## MCE loads MCE::Signal when not present.
                   ## Include MCE::Signal first for options to take effect.

DESCRIPTION

       This package configures $SIG{HUP,INT,PIPE,QUIT,TERM,XCPU,XFSZ} to point to stop_and_exit
       and creates a temporary directory. The main process and workers receiving said signals
       call stop_and_exit, which signals all workers to terminate, removes the temporary
       directory unless -keep_tmp_dir is specified, and terminates itself.

       The location of the temp directory resides under $ENV{TEMP} if defined, otherwise /dev/shm
       if writeable and -use_dev_shm is specified, or /tmp.

       The temp dir resides under $ENV{TEMP}/mce/ for native Perl on Microsoft Windows.

       As of MCE 1.405, MCE::Signal no longer calls setpgrp by default. Pass the -setpgrp option
       to MCE::Signal to call setpgrp.

        ## Running MCE through Daemon::Control requires setpgrp to be called
        ## for MCE releases 1.511 and below.

        use MCE::Signal qw(-setpgrp);   ## Not necessary for MCE 1.512 and above
        use MCE;

       The following are available arguments and their meanings.

        -keep_tmp_dir     - The temporary directory is not removed during exiting
                            A message is displayed with the location afterwards

        -use_dev_shm      - Create the temporary directory under /dev/shm

        -no_sigmsg        - Do not display a message when receiving a signal
        -no_kill9         - Do not kill -9 after receiving a signal to terminate

        -setpgrp          - Calls setpgrp to set the process group for the process

                            This option ensures all workers terminate when reading
                            STDIN for MCE releases 1.511 and below.

                               cat big_input_file | ./mce_script.pl | head -10

                            This works fine without the -setpgrp option:

                               ./mce_script.pl < big_input_file | head -10

       Nothing is exported by default. Exportable are 1 variable and 2 subroutines.

        $tmp_dir          - Path to the temporary directory.
        stop_and_exit     - Described below
        sys_cmd           - Described below

   stop_and_exit ( [ $exit_status | $signal ] )
       Stops execution, removes temp directory, and exits the entire application.  Pass 'TERM' to
       terminate a spawned or running MCE state.

        MCE::Signal::stop_and_exit(1);
        MCE::Signal::stop_and_exit('TERM');

   sys_cmd ( $command )
       The system function in Perl ignores SIGNINT and SIGQUIT. These 2 signals are sent to the
       command being executed via system() but not back to the underlying Perl script. For this
       reason, sys_cmd was added to MCE::Signal.

        ## Execute command and return the actual exit status. The perl script
        ## is also signaled if command caught SIGINT or SIGQUIT.

        use MCE::Signal qw(sys_cmd);   ## Include before MCE
        use MCE;

        my $exit_status = sys_cmd($command);

EXAMPLES

        ## Creates tmp_dir under $ENV{TEMP} if defined, otherwise /tmp
        use MCE::Signal;
        use MCE::Signal qw( :all );

        ## Attempt to create tmp_dir under /dev/shm if writable
        use MCE::Signal qw( -use_dev_shm );

        ## Keep tmp_dir after script terminates
        use MCE::Signal qw( -keep_tmp_dir );
        use MCE::Signal qw( -use_dev_shm -keep_tmp_dir );

INDEX

       MCE

AUTHOR

       Mario E. Roy, <marioeroy AT gmail DOT com>