compiletools

C/C++ build tools that requires almost no configuration.

NOTE:	The repository-level README.rst is a symlink to this file, so they are the same canonical document.
Author:	drgeoffathome@gmail.com
Date:	2026-05-09
Version:	10.0.3
Manual section:	1
Manual group:	developers

SYNOPSIS

ct-* [compilation args] [filename.cpp] [--variant=<VARIANT>]

DESCRIPTION

compiletools provides C/C++ build automation with minimal configuration. The tools automatically determine source files, dependencies, and build requirements by analyzing your code.

To build a C or C++ project, simply type:

ct-cake

This automatically determines source files, builds executables, and runs tests. See ct-cake(1) for details.

QUICK START

Try compiletools without installing using uvx:

uvx --from compiletools ct-cake
uvx --from compiletools ct-compilation-database

This runs tools directly without affecting your system. All ct-* tools work with uvx (e.g., uvx --from compiletools ct-config).

INSTALLATION

uv pip install compiletools

Or for development:

git clone https://github.com/DrGeoff/compiletools
cd compiletools
uv pip install -e ".[dev]"

EXAMPLES

Two example trees ship with the package:

• src/compiletools/examples-end-to-end/ — buildable mini-projects exercising the full ct-cake --auto pipeline (PCH, C++20 modules, static / dynamic libraries, multi-target apps, sanitizer variants, pkg-config, …). Each has a README describing what it demonstrates; cd into one and run ct-cake to see the build flow end-to-end.
• src/compiletools/examples-features/ — focused, fixture-style projects for individual magic-flag annotations and config features (//#PKG-CONFIG=, //#LDFLAGS=, //#PCH=, append-style variables, …). Useful as copy-paste templates when adding the same feature to your own project.

The examples_registry Python module (example_path(), example_file()) maps these trees from test code; tests under src/compiletools/test_*.py use them as fixtures, so each example is also a worked CI-verified configuration.

KEY FEATURES

Magic Comments

Embed build requirements directly in source files using special comments like //#LDFLAGS=-lpthread or //#PKG-CONFIG=zlib. See ct-magicflags(1).

Automatic Dependency Detection

Traces #include statements to determine what to compile and link. No manual dependency lists needed.

Build Variants

Support for debug, release, and custom build configurations. Use --variant=release to select. See ct-config(1).

Pluggable Build Backends

Choose from Make (default), Ninja, CMake, Bazel, or the builtin Shake backend. Distribute compilation across an HPC cluster with the Slurm backend. Use --backend=<name> to select. See ct-backends(7).

Content-Addressable Caching

Objects, precompiled headers, C++20 module BMIs, and the linker artefacts themselves (executables, static libs, shared libs) are cached in per-variant content-addressable directories (cas-objdir, cas-pchdir, cas-pcmdir, cas-exedir). Cache keys are anchored to the git root, so identical translation units share entries even when the workspace is moved or cloned to a new path. Combined with the default --use-mtime=False, fresh-checkout CI builds (where every source has mtime=now) hit the cache instead of re-running the producer. Trim with ct-trim-cache.

C++20 Modules

First-class support for clang .pcm and gcc .gcm BMI artefacts -- including named modules, partitions, header units, and import std -- with automatic discovery from import / export module in your sources. See the C++20 Modules Caching section in ct-cake(1).

Precompiled Headers

Mark headers with //#PCH= and ct-cake builds them once and shares them across the project via cas-pchdir.

File Locking

Multi-user/multi-host object file caching with filesystem-aware locking for faster builds in team environments. Enable with file-locking = true.

Minimal Configuration

Works out-of-the-box with sensible defaults. Configuration only needed for customization.

CORE TOOLS

ct-cake

Main build tool. Auto-detects targets, builds executables, runs tests.

ct-compilation-database

Generate compile_commands.json for IDE integration. Auto-detects targets.

ct-config

Inspect configuration resolution and available compilation variants.

ct-magicflags

Show magic flags extracted from source files.

ct-headertree

Visualize include dependency structure.

ct-filelist

Generate file lists for packaging and distribution.

ct-timing-report

Analyze build timing data from ct-cake --timing. Interactive TUI, static summary, run comparison, and Chrome Trace export.

ct-trim-cache

Trim aged entries from the object, PCH, PCM, and linker-artefact content-addressable caches with configurable retention.

ct-cache-report

Summarize content-addressable cache occupancy and flag duplication in the object, PCH, PCM, and linker-artefact caches.

ct-cas-publish

Helper invoked from generated build recipes: atomically publish a cas-exedir entry to a user-facing bin/<variant>/<name> path via link() + rename(), with EXDEV-only symlink fallback. Not normally run by hand.

ct-cleanup-locks

Clean stale locks from file locking.

ct-check-venv

Verify that the ct-cake on PATH imports the same compiletools as the active venv. Run after git worktree add and a fresh uv pip install -e . to confirm subprocess-driven tools see the expected source tree.

ct-list-backends

List available build backends (make, ninja, cmake, bazel, shake).

Shell Wrappers

Convenience scripts in scripts/: ct-build, ct-build-static-library, ct-build-dynamic-library, ct-watch-build, ct-lock-helper, ct-release.

CONFIGURATION

Options are parsed using ConfigArgParse, allowing configuration via command line, environment variables, or config files.

Configuration hierarchy (lowest to highest priority):

• Executable directory (ct/ct.conf.d alongside the ct-* executable)
• System config (/etc/xdg/ct/)
• Python virtual environment (${python-site-packages}/ct/ct.conf.d)
• Package bundled config (<installed-package>/ct.conf.d)
• User config (~/.config/ct/)
• Project config (<gitroot>/ct.conf.d/)
• Git repository root directory
• Current working directory
• Environment variables (capitalized, e.g., VARIANT=release)
• Command-line arguments

Build variants are composed from axis conf files — one per orthogonal concern: toolchain (gcc, clang), linker (ld, gold, mold, wild), optimization (debug, release), instrumentation (asan, ubsan, tsan, coverage, lto). --variant=gcc,debug,asan (or gcc.debug.asan or gcc debug asan — comma, dot, and whitespace are all equivalent) synthesizes the composition from gcc.conf + debug.conf + asan.conf. No per- combination conf file is required.

Common usage:

ct-cake --variant=gcc,release             # toolchain + opt
ct-cake --variant=clang,debug,asan        # toolchain + opt + sanitizer
ct-cake --variant=gcc,mold,release,lto    # everything composes
ct-cake --append-CXXFLAGS="-march=native"

For details on configuration hierarchy, file format, and variant system, see ct-config(1).

ATTRIBUTION

This project is derived from the original compiletools developed at Zomojo Pty Ltd (between 2011-2019). Zomojo ceased operations in February 2020. This repository continues the development and maintenance of the compiletools project.

SEE ALSO

• ct-backends (7) -- build backend architecture and selection guide
• ct-build
• ct-build-docs
• ct-build-dynamic-library
• ct-build-static-library
• ct-cake
• ct-cas-publish
• ct-check-venv
• ct-cleanup-locks
• ct-compilation-database
• ct-config
• ct-cppdeps
• ct-create-makefile
• ct-filelist
• ct-findtargets
• ct-git-sha-report
• ct-gitroot
• ct-headertree
• ct-jobs
• ct-list-backends
• ct-list-variants
• ct-lock-helper
• ct-magicflags
• ct-pytest-monitor
• ct-release
• ct-timing-report
• ct-trim-cache
• ct-watch-build