Fix misra 14.4 violation in macro function

Question

I get misra 14.4 violation saying " the condition exprecssion "0" does not have an essential boolean type"

It is a function defined as a macro

How can I fix this violation ?

#define function(a,b,c) do { \

< some -code > \
} while (0)

How can I solve this ?

I tried using while (false) and while (1 == 0) instead of while (0) But the violations was not fixed

Answer 1

The recommendation to use do ... while(0) macros was removed between MISRA C:2004 and 2012 (this might be one of the few places where I actually managed to influence the committee), because MISRA C already has a rule that only compound statements {} are allowed. Meaning that do-while(0) is a counter-productive trick that may hide MISRA violations. In a MISRA context, it is a good thing if code such as if(cond) macro(); yields a compiler error, because it isn't MISRA compliant. And the MISRA compliant if(cond) { macro(); } will not need do-while(0).

Details here: What is do { } while(0) in macros and should we use it?

If you still insist to use such macros then do { ... } while(false) ought to silence the static analyzer.

Also note that 0 in an expression which is intended to be unsigned is yet another MISRA C violation that might annoy the analyzer - 0u would be correct.