A new open-source library called mahler.c brings Western music theory functions to C99 developers. The tool offers interval, chord, scale, and key signature calculations without internal memory allocation. It handles theoretical keys like Fb+ and unlimited accidentals, ensuring enharmonic correctness—such as returning Bb instead of A# for a D minor 6th. The library targets embedded systems and performance-sensitive applications where dependencies are undesirable.

Its 100% test coverage and minimalist design distinguish it from heavier music API frameworks. By avoiding dynamic memory, mahler.c operates predictably in resource-constrained environments. The C99 standard ensures broad compiler compatibility while keeping the codebase small. Developers can integrate it directly into projects without linking external libraries, making it suitable for game audio engines, digital instruments, or educational tools.

Usage examples demonstrate its simplicity. A single function call generates the C4 Blues Scale, returning an array of notes that can be printed with `mah_write_note`. The provided CMake configuration streamlines compilation, requiring only the `src` and `inc` directories. This approach reduces setup friction compared to package managers, appealing to C developers who prefer explicit build control.

The library's name honors composer Gustav Mahler, reflecting the author's admiration for his emotionally complex work. For developers needing reliable music theory computations without bloat, mahler.c provides a focused solution. Its release on GitHub with a permissive license encourages adoption in both hobbyist and professional audio projects where deterministic behavior and low overhead are critical.