Hello @emilie,
Thanks for showing your interest about MISRA related rules and I’m sorry to say it’s not possible to add custom rules for C or C++ in SonarQube. Today, we support MISRA C++ 2008 (see C++ analysis engine covers more rules from MISRA C++ 2008 standard).
Do you confirm you need rules to check your compliance against MISRA C 2004?
Regards
Alex