ct-create-makefile¶

Generate Makefile from compiletools magic¶

Author:: drgeoffathome@gmail.com
Date:: 2024-11-24
Version:: 10.0.6
Manual section:: 1
Manual group:: developers

SYNOPSIS¶

ct-create-makefile [options] [–dynamic lib.cpp] [–static lib.cpp] [–tests test.cpp] filename.cpp

DESCRIPTION¶

ct-create-makefile generates a Makefile from compiletools magic comments and automatic dependency detection. This is the underlying tool used by ct-cake and the ct-build shell scripts.

Unlike ct-cake, which generates and immediately executes the build, ct-create-makefile only generates the Makefile. This is useful when you need to customize the Makefile or inspect the generated rules. For other build system formats, use ct-cake --backend=<name> (choices: ninja, cmake, bazel, shake).

The tool analyzes source files for:

Header dependencies (automatic)
Magic flags (//#LDFLAGS, //#CXXFLAGS, //#PKG-CONFIG, etc.)
Library requirements

OPTIONS¶

–dynamic LIB.cpp: Build a dynamic/shared library from the specified source file. Multiple –dynamic options can be specified.
–static LIB.cpp: Build a static library from the specified source file. Multiple –static options can be specified.
–tests TEST.cpp: Build and register test executables. Multiple –tests options can be specified.

--makefilename NAME: Name of the generated Makefile. Default: Makefile
--variant VARIANT: Use the specified build variant (e.g., gcc.debug, gcc.release). Default: blank
--bindir DIR: Output directory for built binaries. Default: bin/<variant>
--cas-objdir DIR: Output directory for object files. Default: bin/<variant>/obj
--file-locking: Enable file locking for faster rebuilds across projects. Uses content-addressable storage with proper locking.
--no-file-locking: Disable file locking. Default.
--serialise-tests: Run tests sequentially rather than in parallel.
--no-serialise-tests: Run tests in parallel. Default.
--build-only-changed FILES: Only build binaries depending on the specified source or header files. FILES is a space-delimited list of absolute paths to changed files.
--project-version VERSION: Opt in to -DCT_PROJECT_VERSION="<version>" injection into CPPFLAGS/CFLAGS/CXXFLAGS. If neither this flag nor --project-version-cmd is set (on CLI, in ct.conf, or via env), no macro is injected.
--project-version-cmd CMD: Command to run to determine project version (e.g., “git describe”). Opts in to -DCT_PROJECT_VERSION injection the same way as --project-version.
--project-name NAME: Opt in to -DCT_PROJECT_NAME="<name>" injection into CPPFLAGS/CFLAGS/CXXFLAGS. If neither this flag nor --project-name-cmd is set (on CLI, in ct.conf, or via env), no macro is injected.
--project-name-cmd CMD: Command to run to determine project name. The first whitespace-separated token of the command’s stdout is used. Opts in to -DCT_PROJECT_NAME injection the same way as --project-name.
-v, --verbose: Increase output verbosity. Use multiple times for more detail.
--help, -h: Show help message and exit.

EXAMPLE¶

Generate a Makefile for a simple executable:

ct-create-makefile main.cpp

Generate Makefile and then build:

ct-create-makefile main.cpp
make -j$(nproc)

Generate with a shared library:

ct-create-makefile --dynamic mylib.cpp main.cpp
make

Generate for release variant with file locking:

ct-create-makefile --variant=release --file-locking main.cpp
make

COMPARISON WITH CT-CAKE¶

ct-cake and ct-create-makefile serve different purposes:

ct-cake: All-in-one tool that finds targets, generates build files, and runs the build. Supports multiple backends via --backend (make, ninja, cmake, bazel, shake). Use for quick builds during development.
ct-create-makefile: Only generates a Makefile. Use when you need more control over the Make-based build process or want to inspect and customize the generated Makefile.

The ct-build shell scripts use ct-create-makefile internally:

# ct-build is roughly equivalent to:
ct-create-makefile $(ct-findtargets --style=args) "$@"
make -j$(ct-jobs)