Christian Soeller > PDL-2.4.1 > pod2usage

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NAME ^

pod2usage - print a usage message using a script's embedded pod documentation

SYNOPSIS ^

    use PDL::Pod::Usage;
    pod2usage();
    pod2usage(2);
    pod2usage({EXIT => 2});
    pod2usage({EXIT => 2, VERBOSE => 0});
    pod2usage(EXIT => 1, VERBOSE => 2, OUTPUT=\*STDERR);
    pod2usage(VERBOSE => 2);

DESCRIPTION ^

pod2usage will print a usage message for the invoking script (using its embedded pod documentation) and then exit the script with the specified exit value. It takes a single argument which is either a numeric value corresponding to the desired exit status (which defaults to 2), or a reference to a hash. If more than one argument is given then the entire argument list is assumed to be a hash. If a hash is supplied it should contain elements with one or more of the following keys:

EXIT

The desired exit status to pass to the exit() function.

VERBOSE

The desired level of "verboseness" to use when printing the usage message. If the corresponding value is 0, then only the "SYNOPSIS" section of the pod documentation is printed. If the corresponding value is 1, then the "SYNOPSIS" section, along with any section entitled "OPTIONS", "ARGUMENTS", or "OPTIONS AND ARGUMENTS" is printed. If the corresponding value is 2 or more then the entire manpage is printed.

OUTPUT

A reference to a filehandle, or the pathname of a file to which the usage message should be written. The default is \*STDERR unless the exit value is less than 2 (in which case the default is \*STDOUT).

INPUT

A reference to a filehandle, or the pathname of a file from which the invoking script's pod documentation should be read. It defaults to the file indicated by $0 ($PROGRAM_NAME for use English; users).

If neither the exit value nor the verbose level is specified, then the default is to use an exit value of 2 with a verbose level of 0.

If an exit value is specified but the verbose level is not, then the verbose level will default to 1 if the exit value is less than 2 and will default to 0 otherwise.

If a verbose level is specified but an exit value is not, then the exit value will default to 2 if the verbose level is 0 and will default to 1 otherwise.

EXAMPLE ^

Most scripts should print some type of usage message to STDERR when a command line syntax error is detected. They should also provide an option (usually -h or -help) to print a (possibly more verbose) usage message to STDOUT. Some scripts may even wish to go so far as to provide a means of printing their complete documentation to STDOUT (perhaps by allowing a -man option). The following example uses pod2usage in combination with Getopt::Long to do all of these things:

    use PDL::Pod::Usage;
    use Getopt::Long;

    GetOptions("help", "man")  ||  pod2usage(2);
    pod2usage(1)  if ($opt_help);
    pod2usage(VERBOSE => 2)  if ($opt_man);

CAVEATS ^

By default, pod2usage() will use $0 as the path to the pod input file. Unfortunately, not all systems on which Perl runs will set $0 properly (although if $0 isn't found, pod2usage() will search $ENV{PATH}). If this is the case for your system, you may need to explicitly specify the path to the pod docs for the invoking script using something similar to the following:

AUTHOR ^

Brad Appleton <Brad_Appleton-GBDA001@email.mot.com>

Based on code for Pod::Text::pod2text() written by Tom Christiansen <tchrist@mox.perl.com>

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