Re: mingw install directory for shared lib

[Bob Friesenhahn]

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
address@hidden, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/