Re: LinuxPPC1999: shared libraries and dlopen not working ?

[Daniel Jacobowitz <drow@false.org>]

On Sun, Jun 20, 1999 at 03:22:25PM +0200, Gilles Depeyrot wrote:
> Hi,
> 
> I'm having trouble getting shared libraries and dlopen to work under
> LinuxPPC1999.
> 
> I have attached three small files dltest.c, lib1.c and lib2.c. lib1 and
> lib2 must be built as shared libraries and dltest as an executable.
> 
> The test does the following:
> 
> /* dltest
>  * test functionality of dlopen(), dlsym() and dladdr()
>  *
>  * dlopen()  test, w/ and w/o .init function
>  * dlsym()   test, can we retrieve address from symbol
>  * dladdr()  test, given an address, can we find where its from
>  */
> 
> It fails on the first dlopen...

First of all: learn to use dlerror().  It is your friend in places like
this.  It tells me: "Invalid mode for dlopen()".  From glibc I see this
(use the source, Luke!):

  if ((mode & RTLD_BINDING_MASK) == 0)
    /* One of the flags must be set.  */
    _dl_signal_error (EINVAL, file, _("invalid mode for dlopen()"));

You didn't give it a binding mask.  RTLD_GLOBAL isn't enough.  Give it
one of RLTD_NOW or RTLD_LAZY or'd with RTLD_GLOBAL.

All your tests pass after that change.


Dan

/--------------------------------\  /--------------------------------\
|       Daniel Jacobowitz        |__|        SCS Class of 2002       |
|   Debian GNU/Linux Developer    __    Carnegie Mellon University   |
|         dan@debian.org         |  |       dmj+@andrew.cmu.edu      |
\--------------------------------/  \--------------------------------/

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