diff --git a/manual/io_custom_classes/index.md b/manual/io_custom_classes/index.md index afc71181..b09e683a 100644 --- a/manual/io_custom_classes/index.md +++ b/manual/io_custom_classes/index.md @@ -245,7 +245,7 @@ class MyClass { ## Restrictions on types ROOT I/O can handle -For ROOT to be able to store a class, it must have a public constructor. +For ROOT to be able to store a class, it must have a public default constructor or a special I/O constructor (see the documentation of [`TClass::New`](https://root.cern/doc/master/classTClass.html) for more details and examples). ROOT currently does not support I/O of `std::shared_ptr`, `std::optional`, `std::variant` and classes with data members of these types (unless they are marked as "transient").