C++ or C# to program mobile barcode device?

Question

I will be developing some applications using mobile barcode scanners and need to choose between C++ and C# for coding on the scanners.

I am considering Intermec's CK31 or similar for the combination of wifi, scanning choices, programmability and user interface options. It runs Windows CE .NET 4.2 according to their spec sheet.

Intermec's Developer Library comes with .Net and C++ SDKs. My previous Win CE 2003 experience is in C++ (MFC GUI, sockets and serial comms). I'm comfortable in C# with WPF and can learn other GUI frameworks if I have to. That gives me freedom to choose a language - any recommendations one way or another?

I am NOT looking for answers advocating C++ over C# as languages in general - my productivity in either is similar and I have enough experience to be able to create complex, robust C++ solutions.

What I would appreciate are war stories or factors to put into our platform evaluation, about programming on these devices. eg: battery life of C# apps vs C++ apps, memory consumption or other environmental impacts of the language choice. If there are specific versions of .Net CE to avoid, that would be a good tip.

Answer 1

I've been designing and developing software for Windows Mobile and Windows CE in C, C++ and C# for quite a few years now. Moreover, I been doing so for Honeywell (formerly Hand Held Products, purchased by Honeywell in 2007) where I've worked on nearly all aspects of the devices, from drivers and services to Line of Business GUIs and utilities.

First of all, I won't tell you one language is better than the other... I probably spend a 50/50 split of my time with each, and each platform definitely has their own place in the mobile development.

I will however, give a suggestion that you likely stay away from any device that runs an OS as old as WinCE 4.2, especially if you are even considering .NET development. The reasoning for this is that 4.2 only has, at most, .NET CF 1.0 embedded in ROM (part of the OS ROM image), meaning that you would require a ~5MB CAB file to install at least .NET CF 2.0 Yes, you could develop with CF 1.0 but, truly, it's not worth the pain of using such an old framework. Most WinCE 5.0 devices these days come with CF (Compact Framework) 2.0 installed in the ROM so I would at least look for that.

On that same vain, you may even want to consider using a device with Windows Mobile 6.0 or 6.1 as they are easy to program with and will always have CF 2.0 pre-installed. In case you're wondering why I have not mentioned CF 3.0 or CF 3.5, it's just because the first Mobile platform to be release with those versions will be Windows Mobile 6.5, which is not out yet. Though you can always install the framework if you want (~8MB CAB).

Granted, WinCE definitely gives you a more "Windows" look and feel to its GUI over its Windows Mobile cousin, so that is all a matter of your programming preference and what your end users want and need.

Regarding kgiannakakis's comments on SDKs being only a thing layer, this is just not true. If you have a proper SDK you should have all of the same access to any devices or drivers that you would in C++ but with the ease of C#. For example, Honeywell provides an extensive SDK for all of our devices in C++, VB and C# and the C# portion of the SDK actually has more functionality than the C++ portion. You will never have to do a P/Invoke with our code from C#.

If you want to take a look at the SDK I'm talking about, it's freely available to download here and has some great examples. IMHO I would actually consider the provided SDK as more important than the hardware in many cases since, most of the time, the hardware for the devices is pretty much the same. They all have ARM CPUs, WiFi, Bluetooth, Laser or Image based scanners, etc. Though, I looked at the Intermec link you posted and it doesn't look like that unit actually has a built in scanner...are you using an external scanner hooked to the device? Take a look at the Honeywell offering if you want here. We've got devices with probably the best imager based bar code scanner in the business, built into all of our units. And we have a rock solid SDK (I should know, I wrote a lot of it). And the SDK provides .NET extremely access to all of the hardware on the device. Ok...I'll stop my sales pitch now.

As for one language over the other...it really all depends on what exactly you want to do.

Drivers and services cannot be written in anything but Native (Win32) C or C++. So .NET is out for anything like that. C and C++ can absolutely be your friend on mobile devices in terms of keeping things lightweight, since you don't need the whole .NET framework to run the add. Remember, you have a maximum of 32MB of memory for any process (not including DLLs..that's another lecture) so if your application is going to be processing a ton of data, C++ may be the way to go.

One of the major disadvantages I've found to C and C++ on mobile systems, however, is that making a GUI is way harder than it is with .NET Actually, most of the C++ apps I write are completely headless and have no GUI at all... .NET CF does not have WPF (yet), and is stuck with WinForms, but it's really easy to pick up. Pretty much drag and drop in the designer. And also remember, like I mentioned before, that WinCE has a completely different GUI paradigm than Windows Mobile. However, sometimes the Windows Mobile way is kind of nice, since it forces you to keep your GUIs simple and to the point.

Memory consumption can be higher when using .NET, but not always. For one, having a device with the version of the CF you are going to use stored in ROM will mean that you will generally have no more memory used on a .NET application vs the equivalent C++ app. In some cases, .NET will even use less memory. For example, a .NET app vs a C++ app that uses MFC can often use less memory because the C++ app has to load up the MFC framework (since it isn't already loaded by the OS...). Also, since C# is managed, you will often end up with less memory usage because the garbage collector is freeing up memory that you may have forgotten to do in a C++ app.

Execution speed on more modern devices is generally no different between the two. Granted, you will always have little parts of each language where one will be faster than the other, but .NET is mature enough at this point that the speed is not really a concern. I have programmed extremely fast applications with highly interactive, animated GUIs that ran just fine on a device with 128MB RAM and a 420MHz ARM CPU. I even wrote one app that I had to slow down because it was calling into a native DLL via P/Invoke and the .NET portion was essentially getting "Impatient."

I have never seen any issues with battery life in one language vs the other. But I've never specifically tested for it either.

I really think that, in the end, it still comes down to the SDK that comes with your device of choice. If it has poor .NET support then you will find your self doing a lot of extra work getting everything to work, in which case I would go with C++. But if it has great .NET support (like the one I work on) you will find yourself with a lot less work and probably get the job done significantly faster.

Also, remember that it's not just the SDK of the hardware vendor you have to take into account. While you need that specific SDK as each device is different (i.e. the SDK I linked to earlier will not work on that Intermec device) all of the non-hardware related OS stuff is pretty much standard across the board, which is where the Windows Mobile or Windows CE SDK from Microsoft comes in. Their C++ support is pretty good, but they are really pushing all things .NET these days, so as updates are made to the OS, less updates are made to the C++ SDK and much more functionality now relies on using .NET Not that you couldn't do it in C++, it's just that they haven't done a lot of the work for you that they did do in the .NET SDK.

Ok...that was long, but I was trying to dump the finer parts of my years of experience into one thing. I hope it made sense.

Answer 2

The answer to your question has to do with the type of your application. If your application is mainly around communicating with the hardware and only a thin layer of business logic and User Interface is needed, then C++ would be a better choice. To interact with the scanners you need to talk to a driver. This is better and faster achieved with C++. The .NET SDK will actually be a wrapper of C++ code using a ton of P/Invoke, which makes the code performing less faster.

If on the other side your application requires a significant business layer and/or a User Interface, then .NET (and specifically C#) is a better option. In that case the productivity gains far out weight the performance gains of C++.

Another important factor is the type of the devices the application is going to be deployed to. Are you targeting Windows Mobile devices only? Then .NET is a safe option. For Windows CE devices you need to investigate whether the compact framework is pre-installed or not. Also, some Windows CE devices may not support all .NET namespaces.

Finally, I recommend reading Mobile Architecture Pocket Guide, which is a recent document about architectural decisions for mobile applications.