Teach Yourself Borland C++ in 14 Days - portal

136 Day 5
the limits of your knowledge regarding C++. Leave the complicated stuff for next month. But
notice how the framework designers use private, protected, and public access in classes.
Notice how and when they implement inline functions. Notice how things that should be
kept hidden from the user aren’t in public view. Studying a good C++ class library can teach
you a great deal about C++ and object-oriented design.
The C++ Framework Wars
The frameworks need to be separated into two categories: C++ frameworks and VCL. First
I’ll discuss the C++ frameworks and then I’ll move on to VCL. There are really only two viable
C++ frameworks, and they are Borland’s OWL and Microsoft’s MFC.
Borland’s Object Windows Library
Borland took the lead role in the framework race with OWL a few years back. First there was
OWL 1.0. This first version of OWL was a separate product sold by Borland for use with its
Borland C++ 3.0 compiler. (Actually, the very first OWL was written for Turbo Pascal and
was later converted to C++.) OWL 1.0 was a good framework, but because of some
proprietary syntax and other issues, it wasn’t the design that Borland would eventually stick
with for the future of OWL. OWL 1.0 did, however, do the entire Windows programming
community a service—it got the framework ball rolling. Although OWL 1.0 was not the first
framework ever written, it certainly was the first to gain mass-market appeal.
After OWL 1 came OWL 2.0. OWL 2 was a masterpiece. It implemented many of the latest
C++ language features—not because they were new, but because they made sense. Best of all,
OWL 2 was included as part of the Borland C++ 4.0 compiler. From this point on, Borland
would include OWL as part of its Borland C++ package. Borland C++ compilers have always
been first to implement new C++ features, and OWL 2 put those features to good use. OWL
2 also did away with the proprietary syntax that plagued OWL 1. OWL 2 was all standard
C++ that could be compiled with any C++ compiler—at least in theory. As it was, there were
few C++ compilers implementing the latest and greatest C++ features, so OWL 2 was
typically used only with Borland compilers.
Borland released a revision to OWL 2.0 called OWL 2.5. For the most part, the changes were
minor. They were minor in the sense that they didn’t add a lot to OWL 2 itself; a few bug
fixes here and there and a few new classes. But in one way OWL 2.5 was a major release—
it added OLE (object linking and embedding) support in a new set of classes called the Object
Components Framework (OCF). OCF is not technically part of OWL. It works very well
with OWL, but at the same time it can be used independently of OWL.