Show HN: A small, simple music theory library in C99

Source: Hacker News

mahler.c

Simple library for Western music theory in C99.
Repository:
Tests:
Documentation:
Clang format file:

Features

• Small & easy‑to‑use
• Interval, chord, scale, and key‑signature functions
• No internal memory allocation
• Supports theoretical keys (e.g., Fb+)
• No accidental limit (e.g., G 20th sharp)
• Enharmonically correct (e.g., minor 6th of D is Bb, not A#)
• 100 % test coverage

Example

/* Create the C4 Blues Scale, ascending */
struct mah_note notes[7];
struct mah_scale scale = mah_get_scale(
    (struct mah_note){ MAH_C, MAH_NATURAL, 4 },
    &MAH_BLUES_SCALE,
    notes,
    MAH_ASCEND,
    NULL
);

/* Print the scale */
char buf[MAH_DISP_LEN];
for (int i = 0; i 

Who’s Mahler?

Gustav Mahler is one of my favourite composers. If you enjoy the emotions of Wagner and the ideas of Stravinsky, Mahler offers a perfect middle ground. Check out his Symphony No. 5 in C♯ minor, The Song of the Earth, and Symphony No. 6 in A minor.

Documentation

See the full documentation here:

Unit Tests

The test suite is available at:

Compiling

You can build the library with CMake. Be sure to add the src and inc directories to the include path.

cmake_minimum_required(VERSION 3.10)
project(example)

set(MAHLER_PATH "${PROJECT_SOURCE_DIR}/mahler.c")

add_executable(${PROJECT_NAME} ${PROJECT_NAME}.c)

target_include_directories(${PROJECT_NAME} PUBLIC
    "${PROJECT_BINARY_DIR}"
    "${MAHLER_PATH}/inc"
    "${MAHLER_PATH}/src"
)

add_subdirectory(${MAHLER_PATH})
target_link_libraries(${PROJECT_NAME} PUBLIC mahler)

Alternatively, you can compile directly from the command line by including the source and header directories.