Create custom post type with parameters

by

if you are not taking care about backward compatibility (works only when run under PHP 5.3 and later), you can employ the anonymous function:

add_action( 'init', function() {
    $pluralName="PluralName";
    $singularName="SingularName";
    custom_poster( $pluralName, $singularName );
    } 
);

Or closure

$singularName="Singular Name";
$pluralName="Plural Name";
add_action( 'init', function() use ($singularName, $pluralName) {
   custom_poster( $pluralName, $singularName );
} );