On Wed, 9 Jan 2008, Bob Rossi wrote:
There should be no dependencies between plugins.
I don't know. That sentence goes a little to far really. When pcre is
built on windows, it creates two dlls. The first is the regex dll which
supports the POSIX regex functionality. The second is a C++ interface
to the first library. Therefore, the C++ interface depends on the regex
library. Do you think that's bad?
You are saying that POSIX regular expressions is implemented as a
loadable module? That is odd. Normally one would find such things in
a library. Regardless, if care is taken, a module can be used to
implement such functionality without linkage dependency.
There are problems if linkage dependencies are on a module:
1) If module is not available then program (or subsequent modules) do
not run.
2) OS-dependent search/loading procedures are used.
3) Modules need to be loaded in a particular order or else program
fails with an ugly run-time error due to an unresolved symbol (e.g.
Microsoft Windows dialog box) or otherwise mis-behaves.
4) Module namespace needs to be exported globally (not the libltdl
default) so that subsequently-loaded modules may use its symbols.
This is not portable and may result in duplicate symbol issues. Such
modules can never be safely unloaded again.
Where did you get this definition? I don't know, maybe I'm wrong, I
don't have a lot of experience in this area. The pcre behavior comes
I just made it up.
Bob
======================================
Bob Friesenhahn
[EMAIL PROTECTED], http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/
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