Why is this an issue?
Flexible array members are most likely to be used in conjunction with dynamic memory allocation.
The presence of flexible array members modifies the behaviour 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.
Noncompliant code example
uint32_t data[ ]; // Noncompliant - flexible array member
struct s *copy ( struct s *s1 )
struct s *s2 = malloc ( sizeof ( struct s ) + ( s1->len * sizeof ( uint32_t ) ) );
/* Omit malloc ( ) return check for brevity */
*s2 = *s1; /* Only copies s1->len */
- MISRA C:2012, 18.7 - Flexible array members shall not be declared.