Preparing to Know Modern C++

"To know and not do, is to not yet know"

This Zen mantra has been the signature that I have placed at the end of every entry since I started this blog. This mantra is the impetus of this entry, my decision to know how to use Modern C++.

For the past 12 years, I have worked at companies where backwards compatibility and portable software have been crucial for success. This often precludes newer technologies from being adopted for the sake of compatibility. This is unfortunate when considering the recently adopted to C++ standards, C++11 and C++14, which has become collectively known as Modern C++. Portability is one of the most important qualities that I value in software; that is why my personal projects such as Alchemy has not yet incorporated any of the features available in Modern C++.

I believe that this is a mistake, and that I must evolve just as C++ has begun to evolve. This entry is a collection of my thoughts of the features, techniques and challenges that I believe that I will need to learn to become proficient with Modern C++. As much as I can recognize them at this point, I also catalogue some of the rules and idioms from the classic approach that I will need to unlearn to fully take advantage of this new language.

Preparing for the Journey

There will definitely be some challenges in this transition. First, some of the topics like Universal References and Reference Collapsing seem convoluted on the surface. Then as I think I am beginning to understand, I don't think about them for a day or so, and I have lost what I learned. That is why it is important that I apply these techniques while I become familiar with them. Otherwise, there is no reasonable hope that I will ever master them, or even use them correctly.

It is important that I have a project on which I can practice these new techniques. I plan on wrapping up some final issues in Alchemy using C++ with TR1 (Classic C++) and then creating a tag. From that point on, Alchemy will be the instrument that I use to learn and master the techniques in Modern C++. I have studied a few resources with regards to Modern C++, such as Scott Meyer's Effective Modern C++ as well as Stroustrup's recent C++11 - The C++ Programming Language.

The second challenge is rooted in the fact that my current success depends on my ability to remain sharp with the use Classic C++. This does not seem like a difficult task on the surface. For instance, simply remember that range-based for loops, auto and decltype are not available in Classic C++. This is an example of when we tend to over-simplify and abstract away the details of the more subtle differences that exist. A glaring example is the difference in the preferred use of references between the two languages in order to maximize your chances of success with Move Semantics and Perfect Forwarding.

New Language, New Mindset

Thoughts on C++11[^]

Surprisingly, C++11 feels like a new language: The pieces just fit together better than they used to and I find a higher-level style of programming more natural than before and as efficient as ever...

...My ideal is to use programming language facilities to help programmers think differently about system design and implementation. I think C++11 can do that...
    --Bjarne Stroustrup

I have been tentatively studying the additions to Modern C++ since 2011. I tend to agree more and more with Stroustrup's comments on C++11 with each level that I delve deeper into the additional features added to the language. Programming, in general, can be viewed as a very simple task and skill. At its base, you are only commanding a machine to perform specific tasks one step at a time to achieve a goal.

Nuances

That notion is where we all make the mistake from time to time, and forget about the underlying nuances that differentiate how each language is used most effectively. Also the nuances that appear based upon the programming domain that you are operating within; application development differs from database development, which differs from low-level algorithm development, which in turn differs from system-level and device driver development. Then there is the world of web-development, automated scripting and the forms of programming that many may not consider programming, such as developing spreadsheets in Excel.

My skills as a software developer have become so natural that I can effectively pick up the syntax for most other programming languages within a few days. Ask me to make some adjustments to a JAVA application, no problem; develop this test utility in C#, sure thing; augment this Python program, shell scripts or make file system, I'm on it. The thing that differentiates me from a well versed JAVA developer is that I do not yet understand the nuances of JAVA well enough to effortlessly create elegant solutions with the language, unlike the seasoned JAVA developer. It is foolish to think otherwise.

Previous Experience

From time to time, I think back to an automated GUI test tool that I developed for the GUI team at work that uses C#. I used my knowledge of Windows, and hooked into its User Interface Automation library to create flexible UI tests from generated code in a way similar to the UI test features that first appeared in Visual Studio 2010 Ultimate. My solution was robust, it followed roughly the same principles that I use for object-oriented development with C++, and yet my implementation felt clumsy. It was not elegant. Much of the code was duplicated, or required adjustments in multiple locations with each additional feature type that I added.

I was not accustomed to the nuances of C#. I know best, how to develop in C++. My solutions started with the structure of a C++ program, and I adapted the locations where there was no C++ equivalent. If I stumbled upon a practice in C# that was different from C++, I also adapted those practices as well. However, when I finally handed the tool off to an experienced C# developer that would continue to maintain the tool, I felt the need to apologize for my inelegant solutions due to lack of experience with C#.

I believed there was a better solution than what I had been able to create in C#, because I knew I had to steer clear of the troubles that I was running into if I could have developed that tool in C++. I knew how to avoid the code duplication, the multiple locations that must be modified for each new type that is added.

Learning the features and syntax available in a new language is simple. Learning how to use them appropriately is the challenge.

Learning a "Different" Way with Familiar Tools

Learning a new way to do things is not always better, sometimes it is just, different. In some cases, the better method really depends on the context in which it is used. There are many features in Modern C++ that appeal to me. I have wanted to start practicing with them for a very long time (in technological time). However, my primary IDE and compiler, Visual Studio, has not provided support for most of these compelling features until VS2013. With the anticipated release of VS 2015, I will be able to use all of these desired features.

I realize that most of these features have existed in other compilers for quite some time, such as GCC And Clang. Once again, for a living, the type of software that I develop can rarely make use of the latest technology and newest compilers. Generally, I have a parallel make project setup for GCC on another platform, like Linux, that I compile and test along side my Visual Studio projects. Now that my favored tools more completely support Modern C++, I can continue to develop in ways that are familiar to my current processes, as I learn and evolve to be effective with a new form of this language.

What Do I Find Compelling?

If it's not obvious from the theme of my sight and the majority of the topics that I choose to discuss, I prefer maintainability in most circumstances; robustness, security and portability are also qualities that I highly value. All of this goes without saying that correctness is an absolute. An incorrect program is a worthless program.

Many of these topics are chosen directly from Effective Modern C++ because the C++ community helped Scott Meyers select these topics as the features that are likely to be misunderstood. The other features are simply welcome additions that will instantly clean up some of my code, especially my use of templates. Here is the list of topics I plan to explore and document in the near future, in no particular order:

• Range-based for
• Uniform initialization and initializer lists
• Template aliases
• Variadic Templates
• auto, declspec and template type-deduction rules[/codespan]
• "codespan">constexpr
• Scoped and strongly-typed enums
• Delegating constructors
• Explicit conversion operators
• Universal references (&&) and reference collapsing
• Move semantics and perfect forwarding
• Lambda expressions
• Query and control of alignment (especially for Alchemy)
• Threading facilities
  • Multi-threaded memory model
  • Atomics
  • Synchronization constructs
  • Futures and Promises
  • Thread-local storage
• Chrono

There are some features that I am already familiar with and have used for quite some time. These are primarily the extensions to the C++ Standard Library that were added as a part of the Technical Report 1 (TR1) specification. In other cases, they are features that could generally be approximated, but were not generally integrated into the language itself:

• static assertions
• shared_ptr, weak_ptr and unique_ptr
• type_traits

Some of these topics I have written about previously, and I still may decide to write about the others in the future. Because although the class shared_ptr implies that it is only useful for managing pointers, it can be applied in many more contexts to enforce robust resource management in your programs.

Summary

In a way, I feel like I am living in the past watching the future pass me by as C++ continues to evolve. When in fact I have actually been practicing modern C++ development for many years now. Only, now there exist better tools and forms of the language to express these same techniques. The advantages gained by employing these new tools lead to more readable code, more explicit intent by the author, and improved forms of syntax to make things that have already existed more convenient to use; constructs like the std::algorithm library.

I have enjoyed using C++ through-out my entire career. I enjoy having one foot touching the system where each byte counts, and the other at a much higher more abstract level creating expressive constructs that feel naturally integrated within the language. The designers of C++ have always made a conscious effort to remain backward compatible to support existing programs, without considering C, stretches almost 35 years. I think it is important to understand how to effectively apply the latest capabilities of C++; especially when considering its integration into existing programs.

That is exactly what I intend to do.