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C++ Class Frameworks and the Visual Component Model
The latest and greatest OWL is 5.0. OWL 5 represents significant enhancements to
OWL 2.5. The primary changes come in new OWL classes that encapsulate the new Win32
custom controls. OCF was also updated in the OWL 5.0 release.
OWL’s strengths are considerable. First, it is an architectural wonder. It is obvious that OWL
was very well thought out from the beginning. I can’t say enough about my admiration for
OWL designers Carl Quinn, Bruneau Babet, and the other OWL team members. OWL is
very OOP friendly and follows all the OOP rules. Its level of abstraction strikes a good balance
between ease of use and power. OWL has one major advantage over its competitors: It can
be used in both 16-bit and 32-bit programs. Borland has even emulated some of the
32-bit custom controls for use in 16-bit programs. While these emulations are not perfect in
all cases, they are usable and give you a method of getting the 32-bit look and feel even in
16-bit programs.
OWL also has its weaknesses. Ironically, one of OWL’s strengths leads, in some people’s
minds, to one of its weaknesses. OWL has done a great job of encapsulating the Windows
environment and that is certainly a strength. Part of the problem with that level of
encapsulation is that OWL is complex, and it is sometimes difficult to find your way around
when you are first learning OWL. The complexity of OWL is considered by some to be one
of its weaknesses. It takes time to master, no question about it. But once you have mastered
OWL, you can be very efficient in writing Windows programs.
The Microsoft Foundation Class Library
Sometime between OWL 1 and OWL 2, the Microsoft Foundation Class (MFC) Library
was born. MFC is included as part of Microsoft’s Visual C++ compiler package. Actually,
versions of MFC ship with compilers by Symantec, Watcom, and, believe it or not, Borland
(there may be others as well). Typically Microsoft has not licensed the most current version
of MFC to other compiler vendors (Symantec and Watcom), but Borland C++ 5.01 included
MFC version 4.1, which at the time was the latest version of MFC (a newer version, 4.2, came
out shortly thereafter).
It could be said that MFC is a different type of class library than OWL. MFC is less abstract
and lies closer to the Windows API. MFC’s strengths come in three primary areas. First, it
is relatively easy to learn. (Understand that no C++ framework dealing with Windows
programming is going to be easy to learn, but MFC is a little easier to pick up than the
competition.) It is easier to learn primarily because it is less abstract in some areas. If you are
new to Windows programming, you will probably find OWL and MFC about equal when
it comes to learning the framework. If you are coming from a C programming background
and already know the Windows API, MFC is almost certainly going to be easier to learn.
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