Opam depext and system package versions

Ecosystem
1

I’m preparing to release an OCaml interface to RocksDB, developed using a C++ FFI generator tool (cppffigen). It turns out that starting at version 7.0.0, RocksDB made a bunch of breaking changes, so I want to prereq rocksdb, but with a version constraint on the depext. I’ve searched around, but find no documentation on how to do that in the opam file.

It seems like I could make my own version of conf-rocksdb (maybe conf-rocksdb-ge-8.0.0 ?) in which the “build” step could check the version-constraint, but perhaps there’s a more “built-in” way to do it?

Does anybody know if and how this is supposed to be done?

Thanks in advance.

2

Don’t know if that’s the way it must be done, but conf-zstd does that. See opam info conf-zstd --raw.

Bascially have your conf-rocksdb version be 8.0.0 and check --atleast-version=8.0.0 in pkg-config.

1 Like
3

Oh very nice! Thank you for this, @dbuenzli !