Re: Shared Library and C++ Classes

"Victor Bazarov" <>
Tue, 12 Feb 2008 10:46:21 -0500
Keith Halligan wrote:

Rainer Lehrig wrote:

An advantage of a shared library is,
that you don't need to relink your apps
if you do not change the interface of the library.

If you add a new method to a class,
will you have to relink the apps, that use the lib ?

As others have said once it's a non-virtual member then you should be

Some other things that will break binary compatibility of a shared lib
on most compilers are:
-> Reordering virtual members
-> Making a function virtual
-> Reordering base classes
-> Adding or removing a base class
-> Adding or removing a data members (if this class is exported)

Adding or removing private static data members should be OK. Here's
a trick some may find useful. When adding a regular data member is
not possible, you can add a private class-wide storage of type
'std::map<yourclass*, wanteddatatype>', for example, and store the
emulated non-static "members" by keying them off 'this' pointers.
Ugly, but sometimes you have to do it.

-> Reordering data members.

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