Re: Finding Dependencies at Run Time

[Julien Lepiller]

The information is all in the package. You can see for instance store paths 
that are embedded form a store path with:

guix gc --references /gnu/store/…

The mecanism depends a bit on the build system but for C programs, it's embeded 
at build-time in its RPATH. For applications, there are wrappers 
(https://guix.gnu.org/manual/devel/en/html_node/Build-Utilities.html#Wrappers). 
Otherwise, we have to propagate run-time dependencies.

The daemon is no longer involved once packages are built/substituted.

Le 13 juillet 2022 16:56:27 GMT+02:00, Peter Polidoro <peter@polidoro.io> a 
écrit :
>I apologize for a very basic question, but I could not find where this is 
>documented. If a paper or manual page describes this I would be happy to read 
>it.
>
>How, in general, does code in a Guix package find its dependency packages at 
>run time?
>
>Does it potentially work differently for each build system or is the same 
>approach used for all packages?
>
>Are absolute store paths of the dependencies saved at build time in 
>environment variables or symbolic links or something that are accessible to 
>the run time code?
>
>If code in a package looks for dependencies using relative paths, are copies 
>or links to the dependencies saved within the package? Or is that sort of 
>duplication always avoided? Are relative paths converted to absolute store 
>paths somehow?
>
>Is the Guix daemon needed at run time to help packages find each other or is 
>the information needed to resolve all of the dependencies saved into the 
>package at build time?
>
>Thanks!