Miscellaneous utilities that can help make code more readable.
A convenience postfix macro that is equivalent to wrapping the preceding expression with User::LeaveIfError().
fs.Connect() OR_LEAVE;
is equivalent to:
User::LeaveIfError(fs.Connect());
The implementation happens to rely on overloading operator|| for TLeave. However, this macro is not intended for use within general expressions, just to guard individual calls to methods that may return an error code.