I’ve put together a rake-based system for building C and C++ projects.
I’ve called it Rake::Builder, it’s available on GitHub here.
Build systems are complicated by external dependencies: finding third-party headers and libraries. Often there is a specific configuration for each operating system and distribution.
The standard system is GNU’s autoconf system, but it is a nightmare. At the most simple level, you distribute source code with a Makefile.
The problem is that Makefiles are just pure dependency managers - if they don’t find what they need, they just fail.
The solution to that problem is the use of
So, with configure, the user then does the following:
$ sudo make install
But, configure itself is a long file, and it’s is a program: about 6000 lines of shell code.
A few lines:
ac_ext=cpp ac_cpp='$CXXCPP $CPPFLAGS' ac_compile='$CXX -c $CXXFLAGS $CPPFLAGS conftest.$ac_ext >&5' ac_link='$CXX -o conftest$ac_exeext $CXXFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
The solution to having to maintain configure? Generate it!
With autotools, there is a seemingly eternal regress of configuration files and scripts generated by other scripts.
This was my project’s root directory listing before I gave up on autoconf:
AUTHORS COPYING ChangeLog EXAMPLE INSTALL Makefile Makefile.am Makefile.in NEWS README aclocal.m4 autom4te.cache config.h config.h.in config.log config.status configure configure.ac depcomp include install-sh missing objects src stamp-h1 test
Fifteen of those files are involved in the mechanics of autoconf.
Autoconf doesn’t really address the issue of building on various systems and adapting semi-automatically. You still have to add all the settings, but you have to learn where in a myriad of files these settings are to be placed.
Of the autoconf alternatives, rake seems to offer the cleanest solution. Rake itself was apparently created as a build system for C, but out of the box it’s too generic: it’s simply a dependency handling system.
There are already a number of specializations of rake. In Rails projects, and Gem building, Rakefiles handle maintenance, testing, documentation building and packaging.
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Rake::Builder is my attempt to specialise rake to the task of building C and C++ projects.
I’ve got to version 0.0.11 and it now builds the following types of projects:
- QT C++,
This is an example with two build targets: a static library and a test executable, with the test project depending on the library:
Rake::Builder.new do |builder|
builder.target = 'libactive_record_sqlite.a'
builder.source_search_paths = [ 'src' ]
builder.header_search_paths = [ 'include/**/*.h' ]
builder.objects_path = 'objects'
builder.include_paths = [ 'include' ]
builder.library_dependencies = [ 'sqlite3' ]
Rake::Builder.new do |builder|
builder.task_namespace = :test
builder.target = 'active_record_test'
builder.source_search_paths = [ 'test' ]
builder.header_search_paths = [ 'test' ]
builder.objects_path = 'test/lib_objects'
builder.include_paths = [ 'include', 'test' ]
builder.library_dependencies = [ 'sqlite3', 'gtest', 'gtest_main', 'active_record_sqlite' ]
builder.library_paths = [ 'objects' ]
builder.target_prerequisites = [ :'rake:build' ]
builder.default_task = [ :run ]
I’m about to start using Rake::Builder on a sizable C++ project using QT, so I’ll have a chance to see if it handles real world stuff without turning into autoconf.