Changeset 103312 in vbox for trunk/doc

Timestamp:

Feb 12, 2024 1:07:59 PM (11 months ago)

Author:

vboxsync

Message:

docs/VBox-CodingGuidelines: Added warning about type promotion issues when using bitfield values in calculations.

File:

• trunk/doc/VBox-CodingGuidelines.cpp (modified) (1 diff)

trunk/doc/VBox-CodingGuidelines.cpp

@@ -181 +181 @@
  *   <li> Avoid throwing exceptions, always prefer returning statuses.
  *        Crappy exception handling is rewared by a glass of water in the face.
+ *
+ *   <li> Always cast bitfields members to the desired type before using them in
+ *        calculations as Visual C++ and g++/clang++ may use different types.
+ *
+ *        It seems like Visual C++ will use the basetype of the field, while the
+ *        other two will narrow the type down to the number of bits specified
+ *        and then subject it to standard type promotion which typically ends up
+ *        with signed int.
  *
  * </ul>