MISRA C

MISRA C is a software development standard for the C programming language developed by MISRA (Motor Industry Software Reliability Association). Its aims are to facilitate code safety, portability and reliability in the context of embedded systems, specifically those systems programmed in ISO C. There is also a set of guidelines for MISRA C++.

However, there are now more MISRA users outside of the automotive industry than in it: "MISRA has evolved as a widely accepted model for best practices by leading developers in sectors including aerospace, telecom, medical devices, defense, railway, and others."

The first edition of the MISRA C standard, "Guidelines for the use of the C language in vehicle based software", was produced in 1998, and is officially known as MISRA-C:1998.

In 2004, a second edition "Guidelines for the use of the C language in critical systems", or MISRA-C:2004 was produced, with many substantial changes to the guidelines, including a complete renumbering of the rules.

Work has just started on the next revision of the guidelines, which are intended to address use of C99.

As with many standards (eg ISO, BSI Group, RTCA, Incorporated et al) the MISRA C guideline documents are not free to users or implementors.

Rules

MISRAC stands for "Motor Industry Software Reliability Association" C standards

MISRA-C:1998 had 127 rules, of which 93 were required and 34 were advisory; the rules were numbered in sequence from 1 to 127.

The MISRA-C:2004 document contains 141 rules, of which 121 are "required" and 20 are "advisory"; they are divided into 21 topical categories, from "Environment" to "Run-time failures".

Tools

While there exist many software tools that claim to check code for "MISRA conformance", there is no MISRA certification process.

An Exemplar Suite for MISRA-C:2004 is available from the MISRA Forum, which allows tool users to evaluate and compare the checking support provided by the various MISRA tools. Additionally, it gives tool implementors some guidance as to the intent of the Rules within MISRA-C:2004.

Most of the guidelines can be checked using tools that perform static code analysis. The remaining guidelines require the use of dynamic code analysis.

MISRA C Committee

The current MISRA C committee has the following members:

• Andrew Banks, Intuitive Consulting
• Manu Batura, Patni Computer Systems Ltd
• Mark Bradbury, Aero Engine Controls, a Rolls-Royce plc and Goodrich Corporation Joint Venture
• Paul Burden, Programming Research
• Mark Dawson-Butterworth, Zytek Automotive Ltd
• Michael Hennell, Liverpool Data Research Associates Ltd
• Chris Hills, Phaedrus Systems Ltd
• Steve Montgomery, Ricardo plc (Chairman)
• Chris Tapp, Keylevel Consultants Ltd
• Liz Whiting, QinetiQ Ltd

Former members:

• Andrew Burnard, Jaguar Land Rover Ltd
• Gavin McCall, Visteon Engineering Services Ltd

The project management, publication and distribution have been handled by David Ward, MIRA Ltd.

External links

• "Introduction to MISRA C". embedded.com. http://www.embedded.com/columns/beginerscorner/9900659?_requestid=427335. 
• "MISRA C: Safer Is Better". electronicdesign.com. http://electronicdesign.com/Articles/Index.cfm?AD=1&ArticleID=2824. 
• "MISRA C — Some key rules to make embedded systems safer". iar.com. http://www.iar.com/website1/1.0.1.0/474/1/index.php. 
• Software reliability expert Les Hatton. "MISRA C papers". leshatton.org. http://www.leshatton.org/index_SA.html. 
• "Commentary on the first edition of the MISRA C guidelines". knosof.co.uk. http://www.knosof.co.uk/misracom.html. 
• "Automating Compliance to MISRA C/C++ Standards". johndayautomotivelectronics.com. http://johndayautomotivelectronics.com/?p=505. 

References

ar:ميسرا سي de:MISRA-C ja:MISRA-C pl:MISRA C pt:MISRA C sk:MISRA C