Re: More on 32bit/64bit ABIs under Linux

[Alexandre Oliva <oliva@dcc.unicamp.br>]

On Apr 22, 1999, hjl@lucon.org (H.J. Lu) wrote:

>> On Apr 22, 1999, hjl@lucon.org (H.J. Lu) wrote:

>> > You don't want to prepend "-L../foo". We only prepend things like
>> > "-L/foo"

>> How about -L$HOME/lib?

> Don't prepend "/ABI32".

How can it tell?

>> I can't make symlinks in /ABI32 as a regular user.  And I can't do
>> that on every single host of the network from which I might want to
>> mount my home dir and run the application.

> If we don't prepend "/ABI32" to -L$HOME/lib, will that be a problem?

We're supposed to take care of the flags for finding libraries in
non-standard paths, aren't we?

> We only prepend "/ABI32" to -L/foo/bar, if both /foo/bar and
> /ABI32/foo/bar exist.

Then the super-user could play tricks on me by creating
/ABI32/home/oliva/lib :-)

> The current /etc/ld.so.conf can handle multiple ABIs. The run-time
> linker is not a problem. The linker, ld, is a problem.

Why can't it be taught to hande multiple ABIs too?  I like you idea of
introducing the ABI in the SONAME of the library; why couldn't it also
use it when searching for a library?  So that, when you specify
-mabi=64 (default) -lfoo, it will look for libfoo-64.so, or maybe
lib64.foo.so, if you will, which is less likely to lead to conflicts.
Then we wouldn't need special directories at all: the linker would
search for the library with the appropriate ABI prefix.  If it can't
find it, it would fallback to the traditional library naming scheme,
making sure that the library actually complies to the selected ABI.

-- 
Alexandre Oliva http://www.dcc.unicamp.br/~oliva IC-Unicamp, Brasil
{oliva,Alexandre.Oliva}@dcc.unicamp.br  aoliva@{acm.org,computer.org}
oliva@{gnu.org,kaffe.org,{egcs,sourceware}.cygnus.com,samba.org}
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