Rule Definition
The order of evaluation associated with both the # and ## preprocessor operators is unspecified. Compilers have been known to implement these operators inconsistently, therefore, to avoid these problems, do not use them.

Remediation
Use the # or ## operator at most once in the definition

Violation Code Sample

#define C(x, y) # x ## y // Non-compliant

In the following, if y is joined to z first then the fourth parameter of D will be substituted and
joined to x. Alternatively, if x is joined with y first, then the fourth parameter of D will not be
substituted.
#define D(x, y, z, yz) x ## y ## z // Non-compliant

Fixed Code Sample

#define A(x) #x // Compliant
#define B(x, y) x ## y // Compliant

MISRA C++ 2008, 16-3-1: There shall be at most one occurrence of the # or ## operators in a single macro definition. AUTOSAR, C++ 2014, Rule M16-3-1: There shall be at most one occurrence of the # or ## operators in a single macro definition.