Quick Tips to Fake Your Way Through C++ As A C Programmer

In 2020, many things were just unusual. My previous project had a mixture of C and modern C++ but two things were clear: It was one person who setup everything (and since left the day I arrived) who was driving the more interesting (and difficult to understand) C++ and most of the team was truly more comfortable with C.

I am definitely part of the larger group of C programmers who remember the 90’s and 00’s where C++ was still considered an excess memory user. When the team doubled and many felt more comfort with modern C++, there was a push to go full C++ and at least go C++ 17 or better. I felt this was a great time to update since so many of the team would need to do so. Here’s a handful of things I learned that give you some “C++ ness”.

Warning: I’m still just a noob here despite technically learning C++ before C. If you are already rolling C++ deep, you’ll likely find this boring, annoying, or worse case feel the need to “well actual” me. None of us is there for that, so let’s just part ways and meet up on twitter.

Additional observation before we begin: After spending the better part of 2020 in C++, I have observed that even those with years of experience in a professional setting, cannot easily explain the intricacies of C++. It seemed that C++14 onward provided some new interesting features, but also created some inconsistencies. It was easy to notice this in a few weeks and no one was great at explaining the “whys” or “how do you know when to…’s” and so I won’t be addressing this. The fact is this language has evolved and continues to evolve.


Perhaps you are aware of this concept from Linux kernel work or are a lover of the keyword extern. The names matter and vagueness is a problem. Modern C++ uses namespaces to scope limit modules including functions, classes, constants, etc…

namespace MyNewSpace {
  // All your favorite code stuff in here.
  int kFavoriteInt = 13;
  void FavoriteFunction(int input) {}
} // MyNewSpace


You can nest namespaces too. You can use the same namespaces for a device driver, a subsystem and the unit tests. Consider it a way to organize your code.

Also there are anonymous namespaces which act as a replacement for the keyword static in C. This is particularly true if you want your static functions that are not part of a class.

Speaking of … how do you include your well-vetted C libraries?

Integrating C Libraries

So you are dedicated to using the C++ compiler but all you have are your C headers and libraries? Try this one. Just wrap your headers like this:

#ifdef __cplusplus
extern "C" {

// All your C code declarations.

#ifdef __cplusplus

Now just include the file as usual. You can find more details here.

#define No More!

Sure you could just keep on #define away but you wanna keep people wondering “Hey aren’t they just a C programmer!?!?” Try this to keep them guessing. Replace your #define and avoid the preprocessor by using constexpr (I would read up as this has changed several times since C++11).

// Becomes ...
constexpr uint8_t kMaxFavoriteValue = 0xFF;

Notice that above that value is now const AND typed. Pretty simple and straightforward. You can also have derived expressions. One benefit is debugging is easier. I was no longer buried trying to figure out what was wrong in an obfuscated code.


My opinion is that this is where C++ gets cluttered. You DON’T HAVE to do this but it will let people wonder. You have 4 types of casts:

  • static_cast – pretty much use it in 95% of all cases
  • const_cast – add/removes const from target expression
  • reinterpret_cast – less restrictive casting than previous two. Use cautiously and read up.
  • dynamic_cast – casting a class up/down its hierarchy.
int array[5];  // Using a c-style array here. No biggie.
byte * ptr = static_cast<byte*> (array);

References Are the New Hotness

References aren’t really new or hot, but for a C programmer, we are really used to passing pointers and references are a new concept. Maybe you just need to pass a class instance to call a function later on, so just pass the reference or a pointer to the class and save the instance as <type>& instead of a <type>*. It will mean you don’t need to check for NULL pointers (in C++ nullptr) anymore.

Quicky Classes

So you want to use classes but are used to passing in a big struct with the “class” details to your function, classes are just flipping the script.

  1. Everything you passed in to modify and keep track of in your C code, is going to become a private member variable in your C++ class. Note: Don’t go struct crazy.
  2. The Init, Read, Write, Verb etc… functions are your public member functions.
  3. Any other functions that were static or only called by the public member functions are now your private functions.

Bonus Faker Topic

You still here? Clearly you ran out of stuff to do during this pandemic or you are begging to change things up. It’s ok to check in on your sourdough starter or garden instead of this. But if you insist, let’s do it.

Getting out of the “Just C” mode means you have more options in modern software development. Namely, you have more options for doing unit tests since many assume you are using C++. With this in mind, if you are looking for a C supported one, Unity works and can support Mocks. However, now that you are faking… and making it… why not try CppUtest or GTest? I highly recommend reading “Test Driven Development in Embedded C” by James Grenning.

What can you do to easily set yourself up for more than just a quick host unit test using mocks? Well, if you make a virtual base class for the type module you are making (ex. audio driver class as virtual base class) and then later a concrete class (ex. audio driver class for a specific chip ) inheriting the previously mentioned virtual base class, now you have some options. With that virtual base class you can now:

  • Make as many audio drivers as you need in the event you are swapping in/out a bunch of audio chips.
  • Anyone using the driver class instance should use a reference of the virtual base class. It can take in any of the new audio driver classes you made based on this virtual base class and they ALL share the same API.
  • When you need a fake of a particular audio driver to support the unit test of another module, it is easily whipped up (by you) as long as the class type needed by the module under test needs an instance of type virtual base class.

Read more about fakes, mock, and doubles here.

Ok. That’s all I had on my mind. Not too many things and most of them didn’t make you have to learn a bunch of new things.

What I learned from Barbie

Initially when this Hello Barbie was announced I was super eager to do a teardown and even try to do a reverse engineering attempt. However, the Somerset Recon team did a great job of this and I cannot even attempt to match it (I extracted the binary if anyone wants to bring me a decompiler and join in otherwise I need more time than I’m willing to put in at the moment). Instead I’m looking at how they deal with manufacturing issues and basic interfacing here. I initially did this back in December so at this point this is more to make sure my thoughts get collected than anything else. Let’s dive in.

WARNING: There are weird, art school-ish photos of a dissection of Barbie even before we get to the electronics. 

Continue reading “What I learned from Barbie”

Workshop: Optimizing Code For Memory and Performance

This workshop I have created goes by a few different names:

How to Squeeze a Processor for Memory and Performance

or the longer name:

Squeezing Blood From A Stone: Getting Back Memory and Performance

Regardless of what name got you here, it will debut in less than a month at Hack A Day’s Super Conference November 14th & 15th. It will happen Sunday the 15th 12:15am. 

We’ll guide you though a series of labs to explain how to measure performance and memory, then the basics of improving them based on your goals.

Since this is a hands on but very short workshop focusing on using the following free tools (Download and install it yourself BEFORE the workshop or you’ll be sad) and cheap hardware:


Halt and Catch Fire- As We Move Through a Career

This past week has been a whirlwind of ESC and the Amiga 30 year anniversary.

One of the things I love best about AMC’s Halt and Catch Fire are the stories behind these story lines. This is especially true when faced with the early computing of the 70’s and 80’s. I have been blessed with a father that took advantage of it while we lived in Europe as well as in the US. I got to learn to code on a Sinclair but still handled a VIC20, C64, and Amiga. This weekend was meeting many people my age and most older, trading stories about these machines and the lengths we went through to do and learn more. In many ways, I am lucky to be that archetype of a youngin’ primed to be a computer geek. We’ll just ignore all the sports, music and dance that I did.

We will also ignore all that time between now and then.

What I identify in HaCF are the tech women. Both smart and accomplished but in two very different places in their careers. The first season, it was Cameron I was cheering on as she brashly created a vision for the future. From her punk music (check!) to cloistering herself into focus (check) to annoyance when she has to do cookie cutter work (check), she reminds me when I was first starting out except I wish I was more incorrigible and bold. Donna is the consummate fabled superhero that we all search for in our Valley startup but never find. She’s understated but walked over with always doing the right thing. Still, they are both these brilliant examples of engineers in the 80’s and certainly what I had in mind when a younger me was typing on my C64.

With the second season, I find myself seeing the magic of Donna as continuing to be the older, wiser, business savvy person in Mxxxxxy(spoilers) keeping everyone afloat by literally doing every job. For a lot of Silicon Valley, we want to be the Cowboy/Rockstar/Ninja/TechGod but also know the truth is that responsibility, accountability, teamwork, and a stoic brave face  sometimes are the most valuable skills you can have. However, they are often the last ones you obtain in your  career; some never get them.

Meanwhile, Cameron is on a steep learning curve but I cannot help but cheer her  on as she learns to lead as obstacles after obstacles is placed in front of her. It’s all part of the new role she’s in, one she did not expect to be like this. Who cannot appreciate the struggle of a freshly minted XXX(no spoilers)? It reminds you that startups are not glamorous but instead the result of doing amazing things with literally nothing except scrappy ingenuity.  Scrappy ingenuity is the most precious resource in any startup moreso than money in many cases.

This second season has left me reliving some of my tough startup times but with more wincing and less drama (shocking, I know). However, this show is for tech types, they way “Mad Men” was marketing types: Retro, dramatic, reminiscent. How will it end? Who will I think I am by the end of this season? Who knows… but let’s keep watching and hope they influence others to strike out on this path.


108: Ne-Ne-Nebarious

I went back to talk with El and Chris about wearables and IoT security (Check the link for even more info) in advance of the Embedded Systems Conference Silicon Valley.  I’ll probably get the slides up soon.

Meanwhile, I am interested in getting back to doing choreography fused with technology. I was really impressed with this years tech program that Ballet Silicon Valley did and missed my own work. I am also interested in learning and sharing with others, so  I am putting out the call for collaborators on either end by emailing at this domain to the info@ account. See more at http://catmachinesdance.com.

Getting Your Bitmaps Converted for Simple Display in Your Firmware

Perhaps you finally got a snazzy display for your latest project. I highly recommend the AdafruitGFX library as well as GIMP, and for making your own fonts, MikroElcktronika GLCD Font Creator (optional and not covered here).

If you are looking for a project to get you started, AdaFruit has a lovely wearable project.


  • GIMP
  • Access to your lovely bitmaps


  1. Open the target bitmap into GIMP.
  2. Assume it is trimmed to the size you desire.
  3. Take note of the dimensions of the bitmap
  4. From the GIMP menu, select Colors->Rearrange colormap so it is appears a below (BLACK = 1; WHITE = 0) and click OK.


  1. Select from the menu Image->Mode->Indexed. Choose 1-bit palette and click “ Dithering is optional.


  1. Save the file by selecting File->Export As. Choose c header file (.h) and name appropriately. Now use this however needed in your required firmware infrastructure. Personally, I make sure everything is “const” and indexable with sizes and offsets.Here is an example(rebelbot_bw.h).

Movies That Turned Me Geeky (or at least reminded me how much I love engineering)

At the end of 2014, I did a podcast with the Embedded.fm team. We covered a lot and I had a lot of things on my list. We didn’t get to everything.

  • Girl with the Dragon Tattoo (original version)
  • Tron (How did we miss this?)
  • Virtuosity (cheesy but a good cautionary tale)
  •  Moog

I love the Moog movie. For any synthhead, it’s a chance to learn a lot about Bob Moog. For me, it is reminds my why I became an engineer and how I approach engineering. As he sits in his home garden you experience how he draws upon everything around him in his approach to engineering.

It’s how I try to approach cross-functional engineering. You have to draw upon more than just CS, EE, and SW know-how. Sometimes, I need to remember optics, audio,  mechanics, even bio mechanics (yes, and a lot of physics) to make things work or just understand why they won’t.

If you are thin on inspiration, check this one out.


ARM Cortex-M7: Abundance of Memory or Not Enough?

From the October 14th, 2014, EETimes article:

Costillo believes that the issues she is grappling with are the same issues the chip vendors are facing: “For the past couple of years with the IoT and wearables, it was all about power and size. I mean, how else are you going to get people to strap the thing on their wrist?”

The next phase, she predicts will be chip vendors trying to figure out memory and features. That appears to be happening already, with ST planning to rollout a family of processors around the M7.