Document how to build with system libs instead of vendored libs about osmexpress HOT 4 OPEN

Is the convention for Nix packages to use dynamic linking instead of static? I have preferred doing as much static linking as possible because it makes my own builds easier.

We can parameterize the CMake file to do one or both of 1) letting the OS defaults handle header search/link paths and 2) prefer dynamic builds for libraries https://github.com/protomaps/OSMExpress/blob/master/CMakeLists.txt#L12

Ideally this isn't specific to NixOS though and works the same way for Debian, for example.

Also, the way the build works is it does depend on a specific minor version of LMDB and capn' proto in order to ensure the binary format is the same across languages. Is that something that NixOS allows?

from osmexpress.

Is the convention for Nix packages to use dynamic linking instead of static?

Dynamic, as with AFAIK most Linux distributions.

We can parameterize the CMake file to do one or both of 1) letting the OS defaults handle header search/link paths and 2) prefer dynamic builds for libraries https://github.com/protomaps/OSMExpress/blob/master/CMakeLists.txt#L12

That'd be great!

Ideally this isn't specific to NixOS though and works the same way for Debian, for example.

I'm pretty sure all distributions would appreciate the possibility of such parametrization. Specifically Debian AFAIK also prefers dynamic linking and system libraries instead of upstream-vendored ones. Which distributions are at all interested in providing a package for OSM Express I don't know. But the parametrization option might also help unofficial packagers (e.g. Debian/Ubuntu PPAs) to provide and maintain clean packages.

from osmexpress.

Also, the way the build works is it does depend on a specific minor version of LMDB and capn' proto in order to ensure the binary format is the same across languages.

Ah, that's good to know.

Is that something that NixOS allows?

Yes, NixOS can provide several variants of a software, e.g. several versions, even when they provide binaries of the same name, and other software can depend on specific variants. It's usually avoided to maintain several variants or versions when it can be avoided, but when there's a good reason (such as here), it can be done.

from osmexpress.

If you comment out most of the include_directories https://github.com/protomaps/OSMExpress/blob/master/CMakeLists.txt#L23

then CMake should look for headers in your system header paths like /usr/local/include, /usr/include, etc I believe. It may be easier to write a new CMakeLists.txt following Nix-specific conventions - maybe using this as a starting point - https://nixos.wiki/wiki/C and then we can figure out how to combine them later.

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