What is DLL Hell?
Most of you
have probably experienced DLL Hell, though you may not have heard of it
described as such. If not, you've probably heard horror stories from friends
goes something like this:
afternoon, SSW, Cameron speaking. How can I help?"
your program doesn't work on my system anymore."
"What seems to be the problem?"
"I don't know - it was working yesterday. There's no error message
or anything - it just doesn't work."
You've just become another victim of DLL Hell.
In a Word
|"All it takes is a single DLL, VBX or OCX to be missing, or present in
an older version... for an application to fail."
another program installed an older DLL, VBX or ActiveX file on their system.
OR maybe a newer, but incompatible version. OR a conflict due to an incompatible
DLL already loaded in memory. OR the PATH environment setting changed.
OR the file properly registered in the registry? OR a required file is
So were we. As you can see, you can literally spend HOURS trying to figure
out what is wrong with a customers machine, and why their applications
will no longer run.
a step back. In the old days, every application was self-contained. A
program would (generally) consist of a single executable file. One thing
was certain - the executables that accompanied a particular application
could be used only by that application. Other products would NOT interfere
the Windows operating environment took advantage of a capability called
dynamic linking to allow code modules to be shared by applications. The
most important demonstration of the use of this capability is Windows
itself - the code modules that contain the functions that make Windows
work (the Windows API), are shared by all Windows applications. A code
module that can be shared in this way is called a dynamic link library
and normally has the extension .DLL.
It is not unusual for users to reinstall software - either during a system upgrade
or to change configurations. In many cases users would install software
that included an older version of a dll ie. commdlg.dll on a system that
already contained a newer version. This would cause the more recently
installed version to replace the newer version. As soon the user attempted
to run the program that required the newer version, problems would occur
ranging from operational difficulties to general protection faults.
framework for programming has had one serious side effect concerning the
distribution of Visual Basic applications. Now instead of a few DLLs that
are shared by several applications, there are hundreds of DLLs, VBXs and
OCXs that may be shared by literally thousands of applications. And all
it takes is a single DLL, VBX or OCX to be missing, or present in an older
version (or even an incompatible newer version), for an application to
fail. A poorly designed installation program, user error, registration
error or change in the user's PATH environment variable are a few of the
ways in which this problem can occur.
two possible ways of finding your way out of DLL Hell:
a browser-based (Thin-Client) solution.
means you only have to worry about one machine. Solve it once and you've
solved it for everyone.
(I guess Microsoft heard these problems loud and clear)
XCOPY deployment solves the registration problem associated with COM.
Taking full advantage of some of these features will require modifying
existing COM components, but we believe that it will save a lot of heart-ache.
are not retiring COM. They're making COM much easier and more productive,
at the same time enabling a totally new kind of softwareWeb services.
Concerned about DLL Hell?
to an SSW Developer about the best solution for you.