Tag Archives: C++11

Your handy cut-out-and-keep guide to std::forward and std::move

Glennan Carnie

Glennan Carnie

Technical Consultant at Feabhas Ltd
Glennan is an embedded systems and software engineer with over 20 years experience, mostly in high-integrity systems for the defence and aerospace industry.

He specialises in C++, UML, software modelling, Systems Engineering and process development.
Glennan Carnie

Latest posts by Glennan Carnie (see all)

I love a good ‘quadrant’ diagram.  It brings me immense joy if I can encapsulate some wisdom, guideline or rule-of-thumb in a simple four-quadrant picture.

This time it’s the when-and-where of std::move and std::forward.  In my experience, when programmers are first introduced to move semantics, their biggest struggle is to know when (or when not) to apply std::move or std::forward.  Usually, it’s a case of “keep apply std::move until it compiles”.  I’ve been there myself.

To that end I’ve put together a […]

Posted in C/C++ Programming | Tagged , , , , , , , | 2 Comments

“May Not Meet Developer Expectations” #77

Glennan Carnie

Glennan Carnie

Technical Consultant at Feabhas Ltd
Glennan is an embedded systems and software engineer with over 20 years experience, mostly in high-integrity systems for the defence and aerospace industry.

He specialises in C++, UML, software modelling, Systems Engineering and process development.
Glennan Carnie

Latest posts by Glennan Carnie (see all)

Question:  Does the following compile?

int func()
{
  int (func);
  return

Posted in C/C++ Programming | Tagged , , , , , | 3 Comments

Exceptional fun!

Glennan Carnie

Glennan Carnie

Technical Consultant at Feabhas Ltd
Glennan is an embedded systems and software engineer with over 20 years experience, mostly in high-integrity systems for the defence and aerospace industry.

He specialises in C++, UML, software modelling, Systems Engineering and process development.
Glennan Carnie

Latest posts by Glennan Carnie (see all)

In this article I want to look at some applications for one of C++’s more obscure mechanisms, the function

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Making things do stuff – Part 9

Glennan Carnie

Glennan Carnie

Technical Consultant at Feabhas Ltd
Glennan is an embedded systems and software engineer with over 20 years experience, mostly in high-integrity systems for the defence and aerospace industry.

He specialises in C++, UML, software modelling, Systems Engineering and process development.
Glennan Carnie

Latest posts by Glennan Carnie (see all)

As a final instalment in this series on hardware manipulation I thought I’d revisit read-only and write-only register types.

Using tag dispatch is not the only way to solve the read- or write-only Register problem.  For completeness let’s explore two other alternatives – SFINAE and constexpr if.

For these examples I’m going to use a simplified version of our Register class.  I’m ignoring the bit proxy class and using a reduced API.  Once understood, the techniques below can be applied to these […]

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Making things do stuff – Part 7

Glennan Carnie

Glennan Carnie

Technical Consultant at Feabhas Ltd
Glennan is an embedded systems and software engineer with over 20 years experience, mostly in high-integrity systems for the defence and aerospace industry.

He specialises in C++, UML, software modelling, Systems Engineering and process development.
Glennan Carnie

Latest posts by Glennan Carnie (see all)

In our previous article we explored using templates to build a generic ‘register’ type to allow programmers to access hardware without all the nasty syntax of integer-to-pointer casting, etc.

At the moment, this class gives us little extra functionality beyond cleaning up the syntax (although, in its favour, it also doesn’t incur any additional run-time cost/performance).

In this article we’re going to extend our design to consider special hardware register types – notably read-only and write-only registers – and see how we can […]

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Making things do stuff – Part 6

Glennan Carnie

Glennan Carnie

Technical Consultant at Feabhas Ltd
Glennan is an embedded systems and software engineer with over 20 years experience, mostly in high-integrity systems for the defence and aerospace industry.

He specialises in C++, UML, software modelling, Systems Engineering and process development.
Glennan Carnie

Latest posts by Glennan Carnie (see all)

As code designers we tend to eschew specific ‘stove-pipe’ code in favour of reusable code elements.  Up until now we’ve been coding some very specific examples so it’s probably worth looking at some more generic solutions.

In this article we’ll look at building generic register manipulation classes (or, as one commenter referred to them, ‘register proxy’ classes).  Here, we’re really exploring code design rather than coding ‘mechanics’.  I’m using this to explore some factors like the balance between efficiency, performance and […]

Posted in C/C++ Programming | Tagged , , , , , , , | 3 Comments

Death and (virtual) destruction*

Glennan Carnie

Glennan Carnie

Technical Consultant at Feabhas Ltd
Glennan is an embedded systems and software engineer with over 20 years experience, mostly in high-integrity systems for the defence and aerospace industry.

He specialises in C++, UML, software modelling, Systems Engineering and process development.
Glennan Carnie

Latest posts by Glennan Carnie (see all)

This time, we’ll have a more detailed look at one of those everybody-knows-that elements of C++ – virtual destructors.

More specifically, I want to reinforce under what circumstances you should make your destructor virtual; and when you don’t need to (despite what your compiler might say)

(*there’s no

Posted in C/C++ Programming, Design Issues | Tagged , , , , , , , , | 9 Comments

Getting your head around auto’s type-deduction rules

Glennan Carnie

Glennan Carnie

Technical Consultant at Feabhas Ltd
Glennan is an embedded systems and software engineer with over 20 years experience, mostly in high-integrity systems for the defence and aerospace industry.

He specialises in C++, UML, software modelling, Systems Engineering and process development.
Glennan Carnie

Latest posts by Glennan Carnie (see all)

Automatic type-deduction is perhaps one of the more divisive features of Modern C++.  At its core it’s a straightforward concept:  let the compiler deduce the type of an object from its initialiser.   Used in the right way this can improve the readability and maintainability of your code.

However, because auto is based on template type-deduction rules there are some subtleties that can catch the unwary programmer.

In this article we’ll have a look at auto in the context of the template type-deduction […]

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Great Expectations

Glennan Carnie

Glennan Carnie

Technical Consultant at Feabhas Ltd
Glennan is an embedded systems and software engineer with over 20 years experience, mostly in high-integrity systems for the defence and aerospace industry.

He specialises in C++, UML, software modelling, Systems Engineering and process development.
Glennan Carnie

Latest posts by Glennan Carnie (see all)

Previously, we’ve looked at the basic concepts of function parameter passing, and we’ve looked at the mechanics of how parameters are passed at the Application Binary Interface (ABI) level.

Far too often we focus on the mechanisms and efficiency of parameter passing, with the goal: if it’s efficient then it’s good; that’s all there is to it.  In this article I want to move past simple mechanics and start to explore function parameter design intent – that is, what can I […]

Posted in C/C++ Programming, Design Issues | Tagged , , , , , , , , | 2 Comments

The three ‘No’s of sequential consistency

Glennan Carnie

Glennan Carnie

Technical Consultant at Feabhas Ltd
Glennan is an embedded systems and software engineer with over 20 years experience, mostly in high-integrity systems for the defence and aerospace industry.

He specialises in C++, UML, software modelling, Systems Engineering and process development.
Glennan Carnie

Latest posts by Glennan Carnie (see all)

In the previous article we looked at the memory consistency problem that occurs when writing multi-threaded code for modern multi-processor systems.

In this article is we’ll have a look at how we can solve the sequential consistency problem and restore some sanity to our programming

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