dlsym can't use handle returned by dlopen?

[Markus Hoenicka]

Don't mean to nag, but is there any news on this?

regards,
Markus

Markus Hoenicka writes:
 > Jeremy Chadwick writes:
 >  > As promised: http://www.malkavian.com/~jdc/myprog.tar.gz
 >  > 
 > 
 > This test program indeed works as expected. However, this doesn't
 > quite reflect the situation in libdbi. I took your files and modified
 > them accordingly, see:
 > 
 > http://libdbi.sourceforge.net/downloads/dlsymtest.tar.gz
 > 
 > To run the test use:
 > 
 > LD_LIBRARY_PATH=. ./myprog
 > 
 > We need to set the environment variable to let the linker pick up a
 > shared object that gmake builds.
 > 
 > myprog.c now just calls a function which is provided in libmylib
 > (built from mylib.c). The latter file does most of what your test case
 > did in myprog.c. The second major change is that myshared.so is linked
 > against libmysqlclient (just like a libdbi database driver is linked
 > against the client library). myfunc now calls a MySQL function to show
 > that it is accessible (if you don't have libmysqlclient handy, you can
 > replace it with whatever function from some .so is convenient)
 > 
 > Finally, libmylib tries to obtain a pointer to that MySQL function by
 > means of a dlsym call. This new dlsym call, in contrast to the existing
 > one that acesses myfunc in myshared.so, indeed fails:
 > 
 > myint = 0xdeadbeef (3735928559)
 > ==> entered myfunc()
 > ==>     double = 3.141590
 > ==>mysql client version is 50051
 > ==> exiting myfunc()
 > dlsym() in shared lib failed: Undefined symbol
 > "mysql_get_client_version"
 > 
 > So, to make the problem clear again: while dlsym works when accessing
 > symbols in dlopen()ed objects, it fails to access symbols which are
 > linked into such an object if you use the handle returned by
 > dlopen(). This is different from other OSes.
 > 
 > regards,
 > Markus
 > 
 > 
 > -- 
 > Markus Hoenicka
 > markus.hoenicka at cats.de
 > (Spam-protected email: replace the quadrupeds with "mhoenicka")
 > http://www.mhoenicka.de
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-- 
Markus Hoenicka
markus.hoenicka at cats.de
(Spam-protected email: replace the quadrupeds with "mhoenicka")
http://www.mhoenicka.de