scons

SCons is an open-source software construction tool that uses Python scripts as build scripts. It replaces traditional makefiles with Python code, allowing developers to describe how to derive targets from source files through conventional programming constructs and logic.

Build scripts and structure are centered on the project’s top-level SConstruct file, which defines the overall environment and build rules, and optional SConscript files in subdirectories for per-subproject rules. SCons builds and maintains a directed acyclic graph of target dependencies, and uses file signatures or timestamps to decide what needs rebuilding, ensuring incremental and deterministic builds. An Environment object encapsulates toolchain settings such as compilers, flags, and libraries, while Builders describe how to construct targets from sources. Users can extend SCons by creating new Builders or by configuring Tools through Python code.

Features commonly cited for SCons include cross-platform support, out-of-tree builds, and automatic dependency scanning for multiple languages via language-specific scanners. It supports parallel builds with command-line options, enabling faster builds on multi-core systems. The tool is highly extensible through Python, allowing customization of build logic, integration with existing toolchains, and the addition of new languages or build steps. SCons provides a library of built-in tools and can be extended with additional Tools modules.

Usage is straightforward for those familiar with Python: run scons in the project root to perform a build, or use options such as -j to parallelize and targets to specify specific outputs. The approach aims to offer robust reproducible builds while remaining flexible for complex build environments.