Programming Embedded Systems in C and C++

146 Chapter 10: Optimizing Your Code

Limiting the Impact of C++

One of the biggest issues I faced upon deciding to write this book was whether or

not to include C++ in the discussion. Despite my familiarity with C++, I had writ-

ten almost all of my embedded software in C and assembly. In addition, there has

been much debate within the embedded software community about whether C++

is worth the performance penalty. It is generally agreed that C++ programs pro-

duce larger executables that run more slowly than programs written entirely in C.

However, C++ has many benefits for the programmer, and I wanted to talk about

some of those benefits in the book. So I ultimately decided to include C++ in the

discussion, but to use in my examples only those features with the least perfor-

mance penalty.

I believe that many readers will face the same issue in their own embedded sys-

tems programming. Before ending the book, I wanted to briefly justify each of the

C++ features I have used and to warn you about some of the more expensive fea-

tures that I did not use.

Of course, not everything introduced in C++ is expensive. Many older C++ compil-

ers incorporate a technology called C-front that turns C++ programs into C and

feeds the result into a standard C compiler. The mere fact that this is possible

should suggest that the syntactical differences between the languages have little or

no runtime cost associated ...