Question

Why does MISRA 14.5 say that the continue statement must not be used?

Answer 1

It is because of the ancient debate about goto, unconditional branching and spaghetti code, that has been going on for 40 years or so. goto, continue, break and multiple return statements are all considered more or less equally bad.

The consensus of the world’s programming community has roughly ended up something like: we recognize that you can use these features of the language without writing spaghetti code if you know what you are doing. But we still discourage them because there is a large chance that someone who doesn’t know what they are doing are going to use the features if they are available, and then create spaghetti. And we also discourage them because they are superfluous features: you can obviously write programs without using them.

Since MISRA-C is aimed towards critical systems, MISRA-C:2004 has the approach to ban as many of these unconditional branch features as possible. Therefore, goto, continue and multiple returns were banned. break was only allowed if there was a single break inside the same loop.

However, in the “MISRA-C:2011” draft which is currently under evaluation, the committee has considered to allow all these features yet again, with a restriction that goto should only be allowed to jump downwards and never upwards. The rationale from the committee said that there are now tools (ie static analysers) smart enough to spot bad program flow, so the keywords can be allowed.

The goto debate is still going strong…