+ * @global array $wp_post_types List of post types.
+ * @global WP_Rewrite $wp_rewrite Used for default feeds.
+ * @global WP $wp Used to add query vars.
+ *
+ * @param string $post_type Post type key, must not exceed 20 characters.
+ * @param array|string $args {
+ * Array or string of arguments for registering a post type.
+ *
+ * @type string $label Name of the post type shown in the menu. Usually plural.
+ * Default is value of $labels['name'].
+ * @type array $labels An array of labels for this post type. If not set, post
+ * labels are inherited for non-hierarchical types and page
+ * labels for hierarchical ones. {@see get_post_type_labels()}.
+ * @type string $description A short descriptive summary of what the post type is.
+ * Default empty.
+ * @type bool $public Whether a post type is intended for use publicly either via
+ * the admin interface or by front-end users. While the default
+ * settings of $exclude_from_search, $publicly_queryable, $show_ui,
+ * and $show_in_nav_menus are inherited from public, each does not
+ * rely on this relationship and controls a very specific intention.
+ * Default false.
+ * @type bool $hierarchical Whether the post type is hierarchical (e.g. page). Default false.
+ * @type bool $exclude_from_search Whether to exclude posts with this post type from front end search
+ * results. Default is the opposite value of $public.
+ * @type bool $publicly_queryable Whether queries can be performed on the front end for the post type
+ * as part of {@see parse_request()}. Endpoints would include:
+ * * ?post_type={post_type_key}
+ * * ?{post_type_key}={single_post_slug}
+ * * ?{post_type_query_var}={single_post_slug}
+ * If not set, the default is inherited from $public.
+ * @type bool $show_ui Whether to generate a default UI for managing this post type in the
+ * admin. Default is value of $public.
+ * @type bool $show_in_menu Where to show the post type in the admin menu. To work, $show_ui
+ * must be true. If true, the post type is shown in its own top level
+ * menu. If false, no menu is shown. If a string of an existing top
+ * level menu (eg. 'tools.php' or 'edit.php?post_type=page'), the post
+ * type will be placed as a sub-menu of that.
+ * Default is value of $show_ui.
+ * @type bool $show_in_nav_menus Makes this post type available for selection in navigation menus.
+ * Default is value $public.
+ * @type bool $show_in_admin_bar Makes this post type available via the admin bar. Default is value
+ * of $show_in_menu.
+ * @type int $menu_position The position in the menu order the post type should appear. To work,
+ * $show_in_menu must be true. Default null (at the bottom).
+ * @type string $menu_icon The url to the icon to be used for this menu. Pass a base64-encoded
+ * SVG using a data URI, which will be colored to match the color scheme
+ * -- this should begin with 'data:image/svg+xml;base64,'. Pass the name
+ * of a Dashicons helper class to use a font icon, e.g.
+ * 'dashicons-chart-pie'. Pass 'none' to leave div.wp-menu-image empty
+ * so an icon can be added via CSS. Defaults to use the posts icon.
+ * @type string $capability_type The string to use to build the read, edit, and delete capabilities.
+ * May be passed as an array to allow for alternative plurals when using
+ * this argument as a base to construct the capabilities, e.g.
+ * array('story', 'stories'). Default 'post'.
+ * @type array $capabilities Array of capabilities for this post type. $capability_type is used
+ * as a base to construct capabilities by default.
+ * {@see get_post_type_capabilities()}.
+ * @type bool $map_meta_cap Whether to use the internal default meta capability handling.
+ * Default false.
+ * @type array $supports An alias for calling {@see add_post_type_support()} directly.
+ * Defaults to array containing 'title' & 'editor'.
+ * @type callback $register_meta_box_cb Provide a callback function that sets up the meta boxes for the
+ * edit form. Do remove_meta_box() and add_meta_box() calls in the
+ * callback. Default null.
+ * @type array $taxonomies An array of taxonomy identifiers that will be registered for the
+ * post type. Taxonomies can be registered later with
+ * {@see register_taxonomy()} or {@see register_taxonomy_for_object_type()}.
+ * Default empty array.
+ * @type bool|string $has_archive Whether there should be post type archives, or if a string, the
+ * archive slug to use. Will generate the proper rewrite rules if
+ * $rewrite is enabled. Default false.
+ * @type bool|array $rewrite {
+ * Triggers the handling of rewrites for this post type. To prevent rewrite, set to false.
+ * Defaults to true, using $post_type as slug. To specify rewrite rules, an array can be
+ * passed with any of these keys:
+ *
+ * @type string $slug Customize the permastruct slug. Defaults to $post_type key.
+ * @type bool $with_front Whether the permastruct should be prepended with WP_Rewrite::$front.
+ * Default true.
+ * @type bool $feeds Whether the feed permastruct should be built for this post type.
+ * Default is value of $has_archive.
+ * @type bool $pages Whether the permastruct should provide for pagination. Default true.
+ * @type const $ep_mask Endpoint mask to assign. If not specified and permalink_epmask is set,
+ * inherits from $permalink_epmask. If not specified and permalink_epmask
+ * is not set, defaults to EP_PERMALINK.
+ * }
+ * @type string|bool $query_var Sets the query_var key for this post type. Defaults to $post_type
+ * key. If false, a post type cannot be loaded at
+ * ?{query_var}={post_slug}. If specified as a string, the query
+ * ?{query_var_string}={post_slug} will be valid.
+ * @type bool $can_export Whether to allow this post type to be exported. Default true.
+ * @type bool $delete_with_user Whether to delete posts of this type when deleting a user. If true,
+ * posts of this type belonging to the user will be moved to trash
+ * when then user is deleted. If false, posts of this type belonging
+ * to the user will *not* be trashed or deleted. If not set (the default),
+ * posts are trashed if post_type_supports('author'). Otherwise posts
+ * are not trashed or deleted. Default null.
+ * @type bool $_builtin FOR INTERNAL USE ONLY! True if this post type is a native or
+ * "built-in" post_type. Default false.
+ * @type string $_edit_link FOR INTERNAL USE ONLY! URL segment to use for edit link of
+ * this post type. Default 'post.php?post=%d'.
+ * }
+ * @return object|WP_Error The registered post type object, or an error object.