The geoarrow C library is a geospatial type system and generic coordinate-shuffling library written in C with bindings in C++, R, and Python. The library supports well-known binary (WKB), well-known text (ISO) and geoarrow encodings as Arrow extension types with all possible mutual conversions including support for Z, M, and ZM geometries.
The library currently implements version 0.1.0 of the GeoArrow specification. The easiest way to get started with GeoArrow is to use the Python bindings, which currently use geoarrow-c under the hood for most operations.