Make opam find a per-user installed C library

Ecosystem
1

this may be easy but i could not see an immediate way to do it.

i’m on a linux machine without admin rights. i have a recent copy of GSL installed in a directory other than the system-wide standard (the sysadmin did this for me, it’s in /opt/gsl-2.4).

how can i

  1. tell opam to install the gsl wrapper with correct linking to this version of GSL
  2. tell ocamlbuild to link correctly afterwards?

i would love to just set some $LD_LIBRARY_PATH and be done with it but that does not seem to be enough?

1 Like
2

Opam doesn’t really have knowledge about the C libraries, so it’s basically down to the packages’ build systems. Setting LD_LIBRARY_PATH (and possibly CPATH) should work, but depending on the ./configure scripts, some might depend on pkg-config, in which case you might have to check with e.g. PKG_CONFIG_PATH too.

All else failing, you might have to tweak the conf-gsl package by hand to make it accept your installation (use opam pin --edit). Opam 2 allows to add setenv: definitions in opam files, so that could be used to avoid having to set the variables each time (or from your .profile) too.

3

thanks! indeed in my case setting both PKG_CONFIG_PATH and LD_LIBRARY_PATH to the appropriate subdirectories of /opt/gsl-2.4 worked!