Error: "Missing mandir" (dune install)

[bentxt]

Expected Behavior

run

 dune install

in a project folder in order to install the project and its built artefact in the default locations

Actual Behavior

> dune install
Error: The mandir installation directory is unknown.
Hint: It could be specified with --mandir

Specifications

> dune --version
3.7.0
> opam --version
2.1.4
> ocaml --version
The OCaml toplevel, version 4.14.1

Additional information

My default mandir directory exists, so no need for specifying a folder I think

ls /usr/local/share/man
de/   ja/   man1/ man3/ man5/ man7/ man8/

Here some additional info on mandir:

https://www.gnu.org/prep/standards/html_node/Directory-Variables.html

‘mandir’
The top-level directory for installing the man pages (if any) for this package. It will normally be /usr/local/share/man, but you >should write it as $(datarootdir)/man. (If you are using Autoconf, write it as ‘@mandir@’.)

[bentxt]

Specifying --mandir was no enough. I had to specify all the locations like this

sudo dune install --mandir=/usr/local/share/man --docdir=/usr/local/share/doc/p5scm --etcdir=/usr/local/etc/ --datadir=/usr/local/share/p5scm --sbindir=/usr/local/sbin --bindir=/usr/local/bin/ --libexecdir=/usr/local/libexec/ --libdir=/usr/local/lib/

Additional problem
--libexecdir=/usr/local/libexec/ is now at a non-standard location since /usr/libexec is non-sudoable on macos

[NielsMommen]

Did you configure dune with custom locations before building it? I know it might happen in that case.

You can also try to pass --prefix=usr/local instead of passing all paths individually. Paths that occur after this option override the prefix path. E.g. --prefix=usr/local --libexecdir=/my/custom/path/to/override/usr/local/libexec

[bentxt]

You can also try to pass --prefix=usr/local

This works thanks

[Alizter]

i think the error message can be improved in this situation so reope ing the issue. Ideally we should suggest the prefix option before mandor.

[bentxt]

Just a note: It seems like the problems I had with dune asking for all this directories was due to lacking Opam initialization.

Now that the Opam init script is invoked during shell initialization, those problems are solved for me.

I wrote also small tip about it in the ocaml forum: https://discuss.ocaml.org/t/tipp-if-opam-gives-you-grief-check-your-init-ba-fi-c-sh-file/12265

[Alizter]

Yes, that probably explains why we don't see this issue so often in the wild. However I have seen and been confused by this message before and I do not use opam so at least we can improve this.