erfa-sys

This crate provides direct bindings to the ERFA C library. It is possible to build the library from C sources, such that the user's system does not need the ERFA C library available as a prerequisite - see static linking below.

Static linking

This crate supports linking to a static build of ERFA. The advantage of doing this is that you don't need the ERFA library available as a system library at runtime.

Static linking can be done in two ways. The first is by using the static feature when building erfa-sys; this compiles erfa-src using your own C compiler.

The second way to link ERFA statically is by providing a liberfa.a library. Either the ERFA_STATIC or PKG_CONFIG_ALL_STATIC environment variable need to be set to 1. The directory containing this file (or the liberfa.so file) can be specified with ERFA_LIB. If ERFA_LIB isn't found, then pkg-config is used to search for the library.

Updating the provided ERFA source code

The erfa-sys/ext directory contains the contents of an ERFA release tarball provided by GitHub. If the source code needs to be changed, then the existing contents should be replaced with another tarball's contents. If the library version has changed, then attempting to build erfa-sys (with e.g. cargo build) should fail; the directory name will need to be changed in erfa-sys/build.rs (the error message from the build is right next to what needs to be changed).

If new ERFA functions or constants are introduced, then gen_rust_include.sh should also be run.

MacOS and/or Windows

I don't have access to these systems, so I don't know how they would work here. Pull requests welcome.

Acknowledgement

This crate was made with a lot of help and inspiration from the hdf5-rust crate family.