RE: g++ 3.0 and empty base classes (was RE: [boost] Re: Review: B oost Coding Guidelines)

From: Gary Powell (Gary.Powell_at_[hidden])
Date: 2001-07-17 13:36:35

-----Original Message-----
From: Jeremy Siek [mailto:jsiek_at_[hidden]]
Sent: Tuesday, July 17, 2001 11:17 AM
To: 'boost_at_[hidden]'
Subject: g++ 3.0 and empty base classes (was RE: [boost] Re: Review:
Boost Coding Guidelines)

[Jeremy Siek]
BTW, I recently confirmed that g++ 3.0 does the empty base class
optimization (older versions did not).

[Gary Powell]
Great!
Last I looked MSVC 6.5 did it if there was one level of inheritance but not
two.

class base {}

class derived : public base {}	// size of data of derived.

class derivedTwice : public derived {}  // non empty inheritance. Dang!

I'm hoping that MSVC 7.1 fixes all, but it may not be able to except for new
platforms, due to running with older versions of the OS.