From 40c94a467daaa83b10e17a89fdeccf5154465eae Mon Sep 17 00:00:00 2001 From: Philippe Canal Date: Thu, 8 Jan 2026 16:37:49 -0600 Subject: [PATCH] Mention ROOT I/O does not support Bit-fields --- manual/io_custom_classes/index.md | 2 ++ 1 file changed, 2 insertions(+) diff --git a/manual/io_custom_classes/index.md b/manual/io_custom_classes/index.md index 2028c096..603b29a1 100644 --- a/manual/io_custom_classes/index.md +++ b/manual/io_custom_classes/index.md @@ -253,6 +253,8 @@ For ROOT to be able to store a class, it must have a public default constructor 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"). +ROOT currently does not support I/O for C++ [`Bit-fields`](https://en.cppreference.com/w/cpp/language/bit_field.html) with a class. + ROOT can store and retrieve data members of pointer type but not reference type. Data members, and in particular pointer data members, _must_ be initialized by the class constructor used by ROOT I/O (most typically, the default constructor):