On Sun, May 10, 2020 at 02:46:39PM +0000, Caveman Al Toraboran wrote: > any reason why it isn't a bug in libstfl? e.g. > shouldn't it create a symlink to libstfl.so.0 as > well?
See [1] and [2] for an overview of the versioning and naming schemes commonly
used by shared objects libraries. `.0` is the major version of the library, and
generally symlinks to the best minor version of that particular major release.
The `.so` suffix, without any particular version number, is usually a symlink to
the latest version installed, regardless of the major version.
Consider the following hypothetical as an exemplar (can an exemplar also be a
hypothetical ?).
libfoo.so.0.2.5
libfoo.so.0 -> libfoo.so.0.2.5
libfoo.so -> libfoo.so.0.2.5
This reflects `libfoo` version 0.2.5, with zero as the major version and 2.5 as
the minor. Now consider that a new major version of `libfoo` is released which
breaks A.P.I.-compatibility with 0.2.5. The files now look like this, assuming
v. 0.2.5 is still on the system:
libfoo.so.0.2.5
libfoo.so.1.0.0
libfoo.so.0 -> libfoo.so.0.2.5
libfoo.so.1 -> libfoo.so.1.0.0
libfoo.so -> libfoo.so.1.0.0
This naming scheme allows application developers, such as those of `newsboat`,
to assume that interface-breakages only occur on changes of the major versions,
thus linking to `<library>.so.<major>` without having to care about the
library's minor versioning.
Unless you're the author of the library to which you're linking, or have some
sort of assurance that your program won't be affected by potential
library interface changes, it's probably a bad idea to link to the symlink with
no specific major or minor version (libfoo.so).
> any guideline that helps us figure out whether its
> an app's fault or a lib's fault?
In your particular case, `newsboat` is trying to link to `libstfl` major version
zero, but unfortunately, the developers of `libstfl` have not included such a
symlink, and instead expect developers to link to files providing a specific
minor version. Technically, it is a problem of `newsboat`, however the authors
of `libstfl` should follow proper versioning practice and provide a symlink for
each major version.
> My thirst for knowledge does not stop here.
;-)
Read more about semantic versioning in the general sense at [3] and [4].
[4] is the Backus-Naur grammar, unneeded for a general understanding of
the concepts unless you're implementing some sort of program to automatically
parse or generate version numbers.
[1] https://stackoverflow.com/a/2004038/
[2] https://stackoverflow.com/a/664401/
[3] https://github.com/dbrock/semver-howto
[4] https://semver.org/
--
Ashley Dixon
suugaku.co.uk
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