Elixir/BEAM bindings for Hamlib — the Ham Radio Control Library — via a Rustler NIF.
This wraps the Hamlib C API (the same surface the JS8Call Android port
drives: rig_init → rig_open → rig_set_freq/rig_get_freq /
rig_set_mode / rig_set_ptt → rig_close → rig_cleanup) and exposes it
to the BEAM. The point is not to reimplement CAT dialects in Elixir — Hamlib
already encodes ~250 rigs' command sets, tested and field-proven — but to make
that library callable from an OTP application.
Architecture
Elixir (Hamlib, Hamlib.Rig) lib/
│ Rustler NIF
Rust (hamlib_nif crate) native/hamlib_nif/src/lib.rs
│ bindgen over a thin C shim
C shim (hlx_* flat functions) native/hamlib_nif/c_src/hamlib_shim.{c,h}
│ links -lhamlib
libhamlib (the actual Hamlib C library)Why a C shim instead of bindgen-on-rig.h?
Hamlib's public headers wrap the hot calls in __builtin_FUNCTION() macros,
e.g. #define rig_set_freq(r,v,f) rig_set_freq(r,v,f,__builtin_FUNCTION()) —
so the real ABI symbol takes an extra trailing const char * the macro injects
for logging. bindgen run directly against rig.h binds the underlying symbol
and loses the macro, which is a footgun. The shim (hamlib_shim.c) #includes
rig.h so the macros apply correctly, owns the RIG * handle lifetime, and
exposes flat hlx_* functions with plain signatures and translated error
codes. bindgen binds the shim, not Hamlib's macro-mangled surface.
Serial I/O on Android (the open question)
On desktop, Hamlib opens a serial device path (/dev/ttyUSB0) and owns the fd.
On Android there is no /dev/tty* access for USB serial — the CP2102 is reached
through the Android USB host API (the same UsbDeviceConnection the modem app
already owns). Bridging Hamlib's serial layer to that fd is the load-bearing
problem for the on-device target and is tracked separately; host development and
testing here use a real serial path or rigctld/dummy rig so the BEAM↔Hamlib
seam can be built and validated before the Android serial bridge lands.
Status
Scaffolding. Host build against Homebrew Hamlib 4.6.5 first; Android NDK cross-compile and the USB-serial bridge follow.