Rule Definition
Flexible array members are most likely to be used in conjunction with dynamic memory allocation. The presence of flexible array members modifies the behavior of the sizeof operator in ways that might not be expected by a programmer. The assignment of a structure that contains a flexible array member to another structure of the same type may not behave in the expected manner as it copies only those elements up to but not including the start of the flexible array member.

Remediation
Define the size of array members.

Violation Code Sample

#include <stdlib.h>
struct s
{
uint16_t len;
uint32_t data[ ]; /* Non-compliant - flexible array member */
} str;
struct s *copy ( struct s *s1 )
{
struct s *s2;
/* Omit malloc ( ) return check for brevity */
s2 = malloc ( sizeof ( struct s ) + ( s1->len * sizeof ( uint32_t ) ) );
*s2 = *s1; /* Only copies s1->len */
return

Fixed Code Sample

unint_16 data[10]

MISRA C 2012, 18.7: Flexible array members shall not be declared