Re: [Plplot-devel] New problems

[Geoffrey F. <fu...@ga...>]

Jo=E3o Cardoso writes:
 >=20
 > The mailing list "reply" is again broken. Just leave it that way, we=
=20
 > will get used to it this way.

The option is gone, I literally can't put it back.  Grrrr.

If anybody comes up with an elisp "list-reply" function that works
with VM, please let me know...  :-).

 > | Thus, the tk problem is another problem. Or maybe not?
 >=20
 > By the way, Geoffrey, you are not working in linux, are you?

Yes, I am on Linux.  I haven't used anything but Linux since joining
Lightspeed.  (Although today I'm gonna have to actually log onto a
Slowaris machine to run some EDA tool that's only provided by the
vendor on Slowaris, but that's just a one time thing.  I live on
Linux).=20

 > The dlopen() man page says:
 >=20
 >        External  references in the library [jc: the dlopened program=
]=20
 >        are resolved using the libraries in that library's dependency=
 =20
 >        list [jc: I (we?) don't want that] and any  other
 >        libraries previously opened with the RTLD_GLOBAL flag
 >=20
 > [jc: so I guess that in linux the loader opens the libraries the=20
 > executable was linked against, with RTLD_GLOBAL, and=20
 > as such their symbols are available to the dlopened program].
 >  =20
 >        If the executable was linked with the flag "-rdynamic",  then=

 >        the  global symbols in the executable will also be used to
 >        resolve references in a dynamically loaded library.

Right.  I believe you understand correctly, everything that relates to
understanding how our C programs, like the PLplot C demos, our own
programs, etc, all work when linked against libplplot, and then using
PLplot's dynamic drivers.=20

Here's what you haven't yet grasped.

When running a /Java/ program, the PLplot binding is accomplished by
asking the JVM to "load" libplplot.  Evidently it does this by dlopen,
but not using RTLD_GLOBAL.  Then, when libplplot dlopen's
driver/xyz.drv, the driver doesn't have access to libplpot's symbols
because libplplot itself wasn't loaded with RTLD_GLOBAL. =20

I'm not defending the JVM behavior, I'm just reporting it.=20

To live with it, we need to either

1) link drivers against libplplot, or
2) break the symbol resolution requirement.

I'll /probably/ check in 1) soon.  I will /possibly/ do 2) sooner than
sometime in the indefinite future.  How's that for a vague statement
of my intentions?  :-).

--=20
Geoffrey Furnish         fu...@ga...