Language subsetting in an industrial context: A comparison of MISRA C 1998 and MISRA C 2004

The MISRA (Motor Industry Software Research Association) C standard first appeared in 1998 with the object of restricting the use of features in the ISO C programming language of known undefined or otherwise dangerous behaviour in embedded control systems in the motor car industry. The first edition gained significant attention around the world and in October 2004, a further edition was issued to a wider intended target audience, with the intention of correcting ambiguous wording undermining the effectiveness of the first edition and also improving its ability to restrict features of dangerous behaviour. This paper measures how well the two versions of this document compare on the same population of software and also determines how well the 2004 version achieved its stated goals. Given its increasing influence, the results raise important concerns, specifically that the false positive rate is still unacceptably high with the accompanying danger that compliance may make things worse not better.