Re: [Plplot-devel] New way of getting device info from dyndrivers

[Rafael L. <lab...@ps...>]

* João Cardoso <jc...@fe...> [2003-02-07 14:51]:

> I measure the time that your code in plInitDispatchTable() takes to load 
> all drivers, and it is only 20ms (wall clock) for all 33 drivers, on a 
> P3@700MHz (with a small but continuous load of 1). It looks like it is 
> pretty efficient.
> 
> Your concerns that dlopen() would load all libraries that a driver needs 
> does not apply, as this would only happens if some drivers code is 
> executed, which is not the case. As libtool's info says:
> 
>     "Unresolved symbols in the module are resolved using
>      its dependency libraries"
> 
> As the symbols you are looking for are in the modules, no further 
> loading will occur.
> 
> Thus, given that the current implementation is efficient enough, avoids 
> the need of another program to build the drivers.rc file, is fully 
> dynamic because if more drivers are added to the directory they will be 
> recognized without further intervention,... lets keep it as is.

Thanks for addressing those two points which I was too lazy to evaluate
(efficiency and loading of libraries).  Although I am not totally happy with
the current implementation, I will keep it as is for now.

I am pretty convinced that the memory management problems that you had when
using lt_dlclose come only from the libltdl code (use of a private realloc
along with a system's malloc).  This has been discussed in the libtool
mailing list and fixed in the libtool's cvs tree.  There are good news here:
version 1.5 is coming soon:

   http://mail.gnu.org/archive/html/libtool/2003-02/msg00014.html

Next step: Debian packages.

-- 
Rafael