Subject: Re: 32 bit & 64 bit libraries.
To: matthew green <>
From: Todd Vierling <>
List: tech-toolchain
Date: 08/12/2001 11:14:15
On Sun, 12 Aug 2001, matthew green wrote:

: what do we want to do?  suggestions off the top of my head (i have no
: real attachment to any of these ideas):
: 	32 bit		64 bit
: 	/usr/lib32	/usr/lib	[*]
: 	/usr/lib	/usr/lib64
: 	/usr/lib	/usr/lib/64
: for [*], while it provides backwards compatibility for NetBSD/sparc64,
: it doesn't truly allow proper sharing of binaries between the 32 bit
: and 64 bit platforms.

`sharing of binaries' depends on exactly what kind of sharing you want.

If the default output of the toolchain on sparc64 will be 64-bit (as it
should--there's a 32-bit kernel config for systems that want a 32-bit
userland), then 32-bit mode is simply binary compatibility:  the 64-bit
libraries belong in /usr/lib.

I personally don't like `/usr/lib32' at all; it's divergent from the tree
structure.  How about `/usr/lib/netbsd32' (to reflect the kernel compat

: also, there's the problem of ld.elf_so:
: 	/usr/libexec/ld.elf_so32	/usr/libexec/ld.elf_so
: 	/usr/libexec/ld.elf_so		/usr/libexec/ld.elf_so64
: 	/usr/libexec/ld.elf_so		/usr/libexec/64/ld.elf_so

This is a little more annoying, because none of these can provide binary
compatibility in a cleanish way.  The /emul/netbsd32 situation works fine
for this, but I know your opinion of that.  8-)

Ideally, again, /usr/libexec/ld.elf_so should be targeted to the default
output of the toolchain for uniformity.  Provided that, an option would be
to provide an in-kernel name substitution (specifically, substitute
something for `/usr/libexec/ld.elf_so' if a binary of the opposite bitsize
is loaded).

Now, I'm not as tied to ld.elf_so being targeted exactly to the toolchain's
default as with /usr/lib.  If, for instance, the default on sparc64 is
64-bit code, then the rtld could be ld.elf_so64.  For compatibility, a
kernel transform, as above, would be usable under COMPAT_15 to remap old
64-bit binaries to use the new rtld name.  (Which would mean that there'd be
no flag day.)

-- Todd Vierling <>  *  Wasabi NetBSD:  Run with it.
-- NetBSD 1.5 now available on CD-ROM  --