One core, every language

Every language reads and writes through the same library: a core written in C++ that implements the format, writing, reading, selecting rows, validating and the built-in model, behind a C interface, gamut.h, which is all the library exports. Each language is a thin layer over that interface, C++ included:

Language	Reaches the core through	Installed as
Python	ctypes	the bijective-gamut wheel, core included
MATLAB	a MEX gateway	the Gamut.mltbx toolbox, core included
Julia	ccall	the package, pointed at a release's core or the wheel's
C++	gamut.hpp, a header over gamut.h	the core built with CMake
C	gamut.h	the core built with CMake
Rust	the bijective-gamut crate over bijective-gamut-sys, the declarations of gamut.h	the crates, linked to a release's core
Command line	the Python package	gamut and gamut-vtk, installed with the wheel

What that means

A file written in one language is read the same in every other, value for value, because one library reads it. A refusal is the same everywhere: the core decides it, and every language reports the rule it names (E7 for units that do not parse), as GamutError.rule in Python and Julia, the error identifier gamut:E7 in MATLAB, gamut::Error::rule() in C++ and Rust, and the gamut_error filled by every C call. A condition passed to select means the same in every language, and the built-in model gives the same answers to the last bit.

The packages carry the core with HDF5 linked inside it, so it never meets another copy of HDF5 in the same process: h5py's, MATLAB's or a solver's.

What differs

Each language spells the calls its own way, and counts positions its own way: from 0 in Python, C++, C and Rust, from 1 in MATLAB and Julia. The codes stored for a label or mesh label count from 0 in every language, since they are part of the file. The reference gives each language's spelling of the same calls.

Some conveniences live in one language. Python converts units on reads and writes (through pint), takes and gives pandas tables, imports and exports VTK, and provides the gamut command line. Model types of your own are registered in Python or MATLAB; Julia, C++, C and Rust evaluate the built-in model.