Bitrix D7 Loader

When to use

• The user is wiring up autoloading for a module's namespaced classes or a custom module's classes — resolving a "class not found" that stems from a module not being loaded, or registering a class autoload map.
• The user needs to include a Bitrix module — Loader::includeModule('iblock') (D7) or the legacy CModule::IncludeModule() — before touching that module's classes, ORM, or functions.
• The user needs to know if a module is present before using it — checking availability, guarding an optional feature, or branching on whether sale, catalog, or a custom module is installed.

When NOT to use