Chess

A portable C library for representing and manipulating chess positions, and generating legal moves. This library provides a clean API for chess engines, GUIs, and tools.

Features

• Full representation of chess positions, moves, and pieces
• Move generation and validation
• FEN parsing and generation
• Algebraic notation parsing and formatting
• Castling, en passant, promotion, and all standard chess rules
• No dependencies required, cmocka is optionally required for testing

Usage

Include the main header in your project:

#include <chess.h>

Example

Creating a new position and generating moves

#include <chess.h>
#include <stdio.h>
 
int main(void) {
  ChessPosition position = chess_position_new();
  ChessMoves moves = chess_moves_generate(&position);
 
  printf("There is %zu legal moves:\n", moves.count);
  for (size_t i = 0; i < moves.count; i++) {
    char buffer[16];
    chess_move_to_algebraic(&position, moves.moves[i], buffer, sizeof(buffer));
    printf("%s\n", buffer);
  }
 
  chess_position_drop(&position);
 
  return 0;
}

Building

This library is written in standard C and should compile with any modern C compiler. It requires at least C11 support. To build using cmake:

cmake -S . -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build

API Overview

• chess_position_new(): Create a new position with the standard starting position
• chess_position_drop(): Destroy the position, freeing all resources held by it.
• chess_moves_generate(): Generate all legal moves
• chess_move_do(): Make a move on a position
• chess_position_from_fen(), chess_position_to_fen(): convert to and from FEN
• *_from_algebraic(), *_to_algebraic(): convert to and from algebraic notation

See the include/chess/ headers for full API documentation.

License

MIT License. See LICENSE for details.