What are the differences between Autotools Cmake and Scons

Choosing the right build system is crucial for any C++ project. A robust build system simplifies the compilation process, manages dependencies, and ensures portability across different platforms. This article delves into the nuances of three popular build systems: Autotools, CMake, and SCons, highlighting their strengths, weaknesses, and ideal use cases. Understanding these differences empowers developers to make informed decisions that streamline their workflow and enhance project maintainability. Navigating the landscape of build systems can be daunting, but by understanding the core functionalities of each, you can confidently select the best tool for your specific needs.

Autotools

Autotools, a collection of tools including Autoconf, Automake, and Libtool, has been a cornerstone of Unix-like systems for decades. It excels at creating highly portable builds, adapting to a wide array of system configurations. This adaptability stems from its configure script, which probes the target system for specific features and dependencies before generating the final build instructions. This dynamic approach makes Autotools ideal for projects requiring maximum portability, particularly across older or less common systems. However, its complexity can be a significant barrier to entry for new users, often requiring a steep learning curve to master its intricacies.

Despite its age, Autotools remains a powerful choice for large-scale projects that prioritize stability and wide platform support. Its mature ecosystem and extensive documentation offer valuable resources for troubleshooting and advanced customization. However, the verbose nature of its configuration files and the sometimes cryptic error messages can be frustrating, especially for smaller projects where simpler alternatives might suffice.

CMake

CMake has emerged as a modern and versatile alternative to Autotools. Its cross-platform compatibility, simpler syntax, and robust feature set make it a popular choice for a wide range of projects. CMake uses a declarative approach, allowing developers to describe the project’s structure and dependencies in a more readable and maintainable format. This streamlined approach reduces the complexity of the build process, making it easier to manage dependencies and customize build configurations.

CMake’s flexibility extends to its integration with various IDEs and build tools, making it a seamless fit into existing workflows. Its active community and extensive documentation provide ample support for both novice and experienced users. Furthermore, CMake’s ability to generate build files for different platforms, including Windows, macOS, and Linux, streamlines the process of creating cross-platform applications. Consider CMake if you’re looking for a balance between power and ease of use.

SCons

SCons, written in Python, offers a unique approach to build management by leveraging the power and flexibility of the Python scripting language. This allows for more complex build logic and customization compared to traditional build systems. SCons’ built-in dependency scanning automatically tracks changes in source files and rebuilds only the necessary components, optimizing build times and reducing development cycles. This automated dependency management simplifies the build process and reduces the risk of errors.

While SCons’ Python-based nature offers significant advantages in terms of flexibility and extensibility, it also introduces a dependency on Python itself. This might be a consideration for projects targeting environments where Python is not readily available. However, for projects that can leverage Python’s capabilities, SCons provides a powerful and customizable build solution. Its inherent cross-platform nature, combined with its Python integration, makes it a compelling option for projects with complex build requirements.

Choosing the Right Build System

Selecting the appropriate build system depends on the specific project requirements. For projects demanding maximum portability across diverse platforms, Autotools remains a robust, albeit complex, solution. CMake offers a good balance of power and ease of use, making it a versatile choice for various project sizes and platforms. SCons’ Python-based approach provides maximum flexibility and customization for projects that can leverage Python’s scripting capabilities. Ultimately, the best choice depends on factors like project complexity, platform requirements, team expertise, and the desired level of control over the build process. No single system is universally superior; the key is to choose the tool that best aligns with your project’s specific needs and the team’s familiarity with the chosen system.

Consider Autotools for maximum portability but be prepared for a steeper learning curve.
CMake offers a good balance of power and ease of use, suitable for a wide range of projects.

Evaluate your project’s specific needs and platform requirements.
Research each build system and consider their strengths and weaknesses.
Choose the system that best aligns with your project goals and team expertise.

For further reading on build systems and software development best practices, visit our blog.

“Choosing the right build system can significantly impact a project’s success. Consider factors like portability, complexity, and team expertise when making your decision.” - Leading Software Engineer

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Autoconf CMake Official Website SConsChoosing the right build system is a critical decision in software development. Carefully weigh the pros and cons of Autotools, CMake, and SCons based on your project’s specific requirements. By understanding the nuances of each system, you can streamline your build process, enhance portability, and improve overall project maintainability. Start exploring these systems today and find the perfect fit for your next C++ endeavor. Explore our other resources on software development best practices to further optimize your workflow.

FAQ:

Q: Which build system is easiest to learn?

A: CMake is generally considered easier to learn than Autotools due to its simpler syntax and more user-friendly documentation.

Question & Answer :
What are the differences between Autotools, Cmake and Scons?

In truth, Autotools’ only real ‘saving grace’ is that it is what all the GNU projects are largely using.

Issues with Autotools:

Truly ARCANE m4 macro syntax combined with verbose, twisted shell scripting for tests for “compatibility”, etc.
If you’re not paying attention, you will mess up cross-compilation ability (It should clearly be noted that Nokia came up with Scratchbox/Scratchbox2 to side-step highly broken Autotools build setups for Maemo/Meego.) If you, for any reason, have fixed, static paths in your tests, you’re going to break cross-compile support because it won’t honor your sysroot specification and it’ll pull stuff from out of your host system. If you break cross-compile support, it renders your code unusable for things like OpenEmbedded and makes it “fun” for distributions trying to build their releases on a cross-compiler instead of on target.
Does a HUGE amount of testing for problems with ancient, broken compilers that NOBODY currently uses with pretty much anything production in this day and age. Unless you’re building something like glibc, libstdc++, or GCC on a truly ancient version of Solaris, AIX, or the like, the tests are a waste of time and are a source for many, many potential breakages of things like mentioned above.
It is pretty much a painful experience to get an Autotools setup to build usable code for a Windows system. (While I’ve little use for Windows, it is a serious concern if you’re developing purportedly cross-platform code.)
When it breaks, you’re going to spend HOURS chasing your tail trying to sort out the things that whomever wrote the scripting got wrong to sort out your build (In fact, this is what I’m trying to do (or, rather, rip out Autotools completely- I doubt there’s enough time in the rest of this month to sort the mess out…) for work right now as I’m typing this. Apache Thrift has one of those BROKEN build systems that won’t cross-compile.)
The “normal” users are actually NOT going to just do “./configure; make”- for many things, they’re going to be pulling a package provided by someone, like out of a PPA, or their distribution vendor. “Normal” users aren’t devs and aren’t grabbing tarballs in many cases. That’s snobbery on everyone’s part for presuming that is going to be the case there. The typical users for tarballs are devs doing things, so they’re going to get slammed with the brokenness if it’s there.

It works…most of the time…is all you can say about Autotools. It’s a system that solves several problems that only really concerns the GNU project…for their base, core toolchain code. (Edit (05/24/2014): It should be noted that this type of concern is a potentially BAD thing to be worrying about- Heartbleed partially stemmed from this thinking and with correct, modern systems, you really don’t have any business dealing with much of what Autotools corrects for. GNU probably needs to do a cruft removal of the codebase, in light of what happened with Heartbleed) You can use it to do your project and it might work nicely for a smallish project that you don’t expect to work anywhere except Linux or where the GNU toolchain is clearly working correctly on. The statement that it “integrates nicely with Linux” is quite the bold statement and quite incorrect. It integrates with the GNU toolsuite reasonably well and solves problems that IT has with it’s goals.

This is not to say that there’s no problems with the other options discussed in the thread here.

SCons is more of a replacement for Make/GMake/etc. and looks pretty nice, all things considered However…

It is still really more of a POSIX only tool. You could probably more easily get MinGW to build Windows stuff with this than with Autotools, but it’s still really more geared to doing POSIX stuff and you’d need to install Python and SCons to use it.
It has issues doing cross-compilation unless you’re using something like Scratchbox2.
Admittedly slower and less stable than CMake from their own comparison. They come up with half-hearted (the POSIX side needs make/gmake to build…) negatives for CMake compared to SCons. (As an aside, if you’re needing THAT much extensibility over other solutions, you should be asking yourself whether your project’s too complicated…)

The examples given for CMake in this thread are a bit bogus.

However…

You will need to learn a new language.
There’s counter-intuitive things if you’re used to Make, SCons, or Autotools.
You’ll need to install CMake on the system you’re building for.
You’ll need a solid C++ compiler if you don’t have pre-built binaries for it.

In truth, your goals should dictate what you choose here.

Do you need to deal with a LOT of broken toolchains to produce a valid working binary? If yes, you may want to consider Autotools, being aware of the drawbacks I mentioned above. CMake can cope with a lot of this, but it worries less with it than Autotools does. SCons can be extended to worry about it, but it’s not an out-of-box answer there.
Do you have a need to worry about Windows targets? If so, Autotools should be quite literally out of the running. If so, SCons may/may not be a good choice. If so, CMake’s a solid choice.
Do you have a need to worry about cross-compilation (Universal apps/libraries, things like Google Protobufs, Apache Thrift, etc. SHOULD care about this…)? If so, Autotools might work for you so long as you don’t need to worry about Windows, but you’re going to spend lots of time maintaining your configuration system as things change on you. SCons is almost a no-go right at the moment unless you’re using Scratchbox2- it really doesn’t have a handle on cross-compilation and you’re going to need to use that extensibility and maintain it much in the same manner as you will with Automake. If so, you may want to consider CMake since it supports cross-compilation without as many of the worries about leaking out of the sandbox and will work with/without something like Scratchbox2 and integrates nicely with things like OpenEmbedded.

There is a reason many, many projects are ditching qmake, Autotools, etc. and moving over to CMake. So far, I can cleanly expect a CMake based project to either drop into a cross-compile situation or onto a VisualStudio setup or only need a small amount of clean up because the project didn’t account for Windows-only or OSX-only parts to the codebase. I can’t really expect that out of an SCons based project- and I fully expect 1/3rd or more Autotools projects to have gotten SOMETHING wrong that precludes it building right on any context except the host building one or a Scratchbox2 one.