FACT SHEET : MISRA C:2012 - PRQA Programming Research

FACT SHEET : MISRA C:2012 The publication date for the new MISRA C:2012 coding standard has now been confirmed as 18th March. We asked Paul Burden, one of the co-authors and PRQA’s representative on the MISRA C Working Group for more than 10 years, to share some insights: Do we need a new MISRA coding standard? PB: MISRA C:2012 (MISRA C3) marks a further step forward in the development of the MISRA C Guidelines. After 14 years of experience drawn from many thousands of users and organizations, lessons are still being learned. This, the third edition, adds some new rules, addresses some loopholes and improves the description and explanation behind existing rules. So what has changed? PB: Some headlines: • Support is provided for C99 as well as C90. • MISRA C3 includes 16 directives & 143 rules. Compliance with a rule can be determined solely from analysis of the source code. Compliance with a directive may be open to some measure of interpretation or may, for example, require reference to design or requirements documents. • Each directive or rule is classified as either Mandatory, Required or Advisory. • Each rule is classified as either a Single Translation Unit rule or a System rule, reflecting the scope of analysis which must be undertaken in order to claim compliance. • The concept of decidability has been introduced in order to expose the unavoidable uncertainty which exists in claiming compliance with certain rules. • Each directive and rule is typically defined with sections devoted to Amplification, Rationale, Exceptions and Examples. What about legacy code which is already compliant to MISRA C2? PB: MISRA C3 does impose some additional requirements but these are relatively few in number and code which is compliant with MISRA C2 is likely to be close to compliant with MISRA C3. Is MISRA C just for use in the automotive industry? PB: Not at all. The principles embraced in MISRA C are not specific to automotive applications. MISRA C has been used for many years in a range of industries including aerospace, railways, nuclear power, medical instruments and commercially critical systems such as finance. Are there any pre-approved/validated/certified MISRA C3 checker tools available? PB: No, MISRA does not endorse tools or provide certification services. However, TERA-Labs, a division of the University of Antwerp, recently completed a comparative study of 8 MISRA C checking tools. Our product, QA·C, was confirmed as the best code analysis tool for enforcing MISRA C2 compliance and we have continued to build on this lead in our enforcement of MISRA C3.

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