>I would like to know why the size of class objects grows when virtual inheritance is involved.
The structure has extra bookkeeping information to keep track.
For example, if you have multiple inheritance of: foo : bar baz : bar quux : foo, baz
The memory layout of quux is going to be: bar foo baz quux
If you pass a quux to something that expects a baz, that routine would expect: bar baz
...it wouldn't expect a "foo" stuck in the middle.
The extra "behind the scenes" bookkeeping information is used to take care of that situation.
I do not think that it is a "onevtable" (whatever that is) related issue.
HTH, --Eljay
