# Decision 0002: C core with FLTK/C++ GUI

**Status:** Accepted

## Context

The project prioritizes a readable, small C implementation while using FLTK
for a lightweight desktop GUI.

## Decision

Keep the engine, DSP, project model, graph, and public core API in C (C99
baseline). Use C++ only for FLTK windows and widgets. Communicate through
documented C headers with `extern "C"` guards.

## Consequences

- No C++ classes, STL containers, exceptions, or FLTK types cross the C API.
- GUI code cannot mutate engine internals directly.
- Keep C++ simple and limited to the presentation layer.