The file below, with two lines commented out, works as I expect.

use strict;
use warnings;
package Sscce;

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

    my ($opt_help, $opt_man,
    );

# sub main {
    GetOptions(
      'help'      => \$opt_help,
      'man'       => \$opt_man,
    ) or pod2usage(-verbose => 1) && exit;

    pod2usage(-verbose => 1) && exit if defined $opt_help;
    pod2usage(-verbose => 2) && exit if defined $opt_man;
# }

1;

=pod

=head1 NAME

=head1 ARGUMENTS

=head1 OPTIONS

  --help       Brief manual
  --man        Full manual
[download]

Running the file gives the output below:

X:\Data\Perl\NoFile>perl Sscce.pm -h
Arguments:
Options:
      --help       Brief manual
      --man        Full manual


X:\Data\Perl\NoFile>perl Sscce.pm -m
NAME
ARGUMENTS
OPTIONS
      --help       Brief manual
      --man        Full manual
[download]

But if the two comment lines are uncommented and the calling command changed, I get an error:

X:\Data\Perl\NoFile>Perl -I. -MSscce -e"Sscce::main @ARGV" -- -h
Can't open -e: No such file or directory at Sscce.pm line 17.
[download]

I fear that I have no idea how to approach this. Adding diagnostics gives more data:

X:\Data\Perl\NoFile>Perl -I. -MSscce -e"Sscce::main @ARGV" -- -h
Can't open -e: No such file or directory at Sscce.pm line 18 (#1)
    (S inplace) The implicit opening of a file through use of the <>
    filehandle, either implicitly under the -n or -p command-line
    switches, or explicitly, failed for the indicated reason.  Usually
    this is because you don't have read permission for a file which
    you named on the command line.

    (F) You tried to call perl with the -e switch, but /dev/null (or
    your operating system's equivalent) could not be opened.

Uncaught exception from user code:
        Can't open -e: No such file or directory at Sscce.pm line 18.
        Pod::Simple::parse_file(Pod::Usage=HASH(0x262f6a8), "-e") call
+ed at C:/Strawberry/perl/lib/Pod/Text.pm line 737
        Pod::Text::parse_file(Pod::Usage=HASH(0x262f6a8), "-e") called
+ at C:/Strawberry/perl/site/lib/Pod/Simple.pm line 535
        Pod::Simple::parse_from_file(Pod::Usage=HASH(0x262f6a8), "-e",
+ GLOB(0x2623f40)) called at C:/Strawberry/perl/lib/Pod/Text.pm line 7
+06
        Pod::Text::parse_from_file(Pod::Usage=HASH(0x262f6a8), "-e", G
+LOB(0x2623f40)) called at C:/Strawberry/perl/lib/Pod/Usage.pm line 17
+9
        Pod::Usage::pod2usage("-verbose", 1) called at Sscce.pm line 1
+8
        Sscce::main(GLOB(0x2623f40)) called at -e line 1
[download]

Unfortunately, going through the code points listed has left me none the wiser. I'd be grateful for any help.

Regards,

John Davies