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WireCell / wire-cell-toolkit

Toolkit for Liquid Argon TPC Simulation and Reconstruction
https://wirecell.github.io/
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Inconsistent installation directory for libs (`lib/` vs `lib64`) #337

Closed brettviren closed 2 months ago

brettviren commented 2 months ago

In some cases a ./wcb install places libraries in

<prefix>/lib/

and in others in

<prefix>/lib64/

I would expect always the former and never the latter but in any case, I'd expect the same behavior on the same OS. However, we see some hosts installing in one and others in the other.

The issue appears to be ultimately due to Waf's Util.lib64() function. On 64bit platform.architecture, it will return "64" if /usr/lib64 exists but /usr/lib32 does not. Otherwise, it returns "".

What is "right"?

FHS 3.0 says /lib holds libraries needed to boot. /lib<qual> MAY be an architecture variant.

Debian supports "multi arch" which is not a simple dichotomy of 32 vs 64 bits. It uses a trio like x86_64-linux-gnu to distinguish. It supplies a /lib64 that contains only a single symlink to the dynamic loader in order to satisfy some ABI standard. Debian also implemented a "merged-/usr" feature which combines all common directories in / and /usr into /usr and thus /lib64 is now seen as a symlink to /usr/lib64. Then, some packages, eg libc6-i386 populate /usr/lib32.

Redhat likes to use lib64/ and has used it traditionally in their attempt to support merely a 32 and 64 bit dichotomy. I don't find must info outside of their paywalled docs.

All in all it seems Util.lib64() makes a bad guess.

It would be good to control this in WCT.

Apparently, this can be forced with something like the following in a wscript:

def configure(cfg):
    cfg.env.LIBDIR = cfg.env.PREFIX + '/lib'

Perhaps added along with a command line option to set it to something else.

brettviren commented 2 months ago

Oops, --libdir is special to waf already which results in library installs going to a "double absolute" path. One can already force a lib dir name with --libdir. What is needed is to force lib/ by default unless user uses --libdir.

HaiwangYu commented 1 month ago

Hi @brettviren, my observations on this: 1, previously the default was lib64 on sl7 container and gpvm 2, the ups building script seems to be able to largely adapt to both: https://cdcvs.fnal.gov/redmine/projects/build-framework/repository/wirecell-ssi-build/revisions/master/entry/ups/wirecell.table#L180

Also I have a question: with https://github.com/WireCell/wire-cell-toolkit/commit/313ec048a090e2fb4228a95b2a9ff159b9f7ce4b, the default is now "lib", right? Do we want to propagate this to the ups system?

brettviren commented 1 month ago

@HaiwangYu Yes, the default is to install libs into lib/. If UPS is okay with that, I suggest letting it use that default. If there is a problem a non-standard location can be set with --libdir.