Re: searching for libraries on RHEL/amd64

[Ralf Wildenhues]

Hi Albert,

* Albert Chin wrote on Sat, May 14, 2005 at 11:14:14PM CEST:
> RHEL [34]/amd64 has /lib64, /usr/lib64, /lib, and /lib64. How do we
> convince libtool to search /lib64, /usr/lib64 first?

RedHat does it with Daniel Reed's patch, which you did not like
(for good reasons).

> Unfortunately, the output of gcc --print-search-dirs is:
>   libraries: 
> =/usr/lib/gcc-lib/x86_64-redhat-linux/3.2.3/:/usr/lib/gcc/x86_64-redhat-linux/3.2.3/:/usr/lib/gcc-lib/x86_64-redhat-linux/3.2.3/../../../../x86_64-redhat-linux/lib/x86_64-redhat-linux/3.2.3/:/usr/lib/gcc-lib/x86_64-redhat-linux/3.2.3/../../../../x86_64-redhat-linux/lib/:/usr/lib/gcc-lib/x86_64-redhat-linux/3.2.3/../../../x86_64-redhat-linux/3.2.3/:/usr/lib/gcc-lib/x86_64-redhat-linux/3.2.3/../../../:/lib/x86_64-redhat-linux/3.2.3/:/lib/:/usr/lib/x86_64-redhat-linux/3.2.3/:/usr/lib/

Yes, ugly.

> The /usr/lib/gcc-lib/x86_64-redhat-linux/3.2.3/../../../ component is
> essentially /usr/lib. So, if /usr/lib/libpopt.so and
> /usr/lib64/libpopt.so are installed, /usr/lib/libpopt.so will be
> selected. Must I LDFLAGS="-L/usr/lib64"?

I'm happy to discuss better solutions.  Changing before 2.0 might be a
good idea.

> Moreoever, libtool.m4 has (from the 2.0 branch):
*snip*
> Why force /lib /usr/lib first here?

"Historic practice"?  Honestly, I don't know.
Actually, Daniel gave good reasoning that /lib and /usr/lib
should not show up in the list _at all_ with -m64.

* Albert Chin wrote on Sat, May 14, 2005 at 11:48:05PM CEST:
> 
> BTW, how about using the SEARCH_DIR directories from:
>   $ ld --verbose
> rather than hardcoding /lib and /usr/lib?

Hmm.  Still has /lib and /usr/lib in there.
Still, the value is no good for sys_lib_dlsearch_path_spec in a true
cross compilation environment, merely for sys_lib_search_path_spec.

I am seriously considering to add command line options to override (or
append/prepend) both of them.  Not only for linux.  Or apply whatever
else we can agree on.  But only if the end result is more cross compile
friendly.

Input solicited.

Regards,
Ralf