Thursday, February 22nd, 2018 by Michael Barr

Barr Group’s 2018 Embedded Systems Safety & Security Survey is now closed and I am in the midst of analyzing the data. This year a portion of my analysis is focused on multi-year trends. One trend that really stands out to me is that the C programming language refuses to give up the ghost.

A longitudinal study of survey data spanning almost a decade and a half shows that C remains the primary programming language of embedded software. Remarkably, in that time C has actually gained market share from 50% to about 70%–at the expense of assembly, C++, and Java.

The graph below shows the relevant data from 2005 through 2018. The first decade of this data is drawn from annual surveys published by the publishers of Embedded.com with the most recent data coming from Barr Group’s annual survey. Each of these surveys of embedded systems designers phrased the relevant question similarly, either “My current embedded project is programmed mostly in [pick one]” or “What is the primary programming language for your current project? [pick one]”.

It makes total sense that the use of assembly language as a primary programming language is falling. The last time I wrote an embedded program mostly in assembly was about twenty years ago. Of course, there will always be some low level code that needs to be written in the native language of the machine–if only to bring up the higher-level language execution and for drivers and kernel code. But with inexpensive (and mostly 32-bit ARM-based) microcontrollers increasingly at the heart of our systems there’s no sense wasting time coding the application code in assembly.

We can attribute about 7 percentage points of the growth in use of C to the reduction in use of assembly during these years. This trend has helped use of C grow to about 60%.

But what’s also been happening in this time is that C++ has failed to capitalize on earlier gains. The peak year for C++ use was apparently 2006, when it had 33% share. Use of C++ as the primary language has since fallen and thus added about 10 percentage points to use of C.

I didn’t include Java in the graph, but it’s use has been less common than assembly in every survey year, with high points of 3% and now down around 1% the last three years. And no other language has emerged to maintain greater than 1% share.

What I make of all of this is that C remains the most cost-effective way to write embedded software. In hindsight, object-oriented languages have been tried but failed to establish their value to most programmers. C++ is a player but looks unlikely to ever eclipse its namesake.

What do you see in the data?

Tags: embedded, firmware, programming, trends