This is a draft version of a MISRA C++ 202x rule proposed for public review.
MISRA Rule 26.3.1
Category: Advisory
Analysis Type: Decidable,Single Translation Unit
Rationale
The std::vector< bool > specialization’s behaviour differs from that of other uses of std::vector as it uses
optimized space allocation. For example, the data member function is not available.
The C++ Standard guarantees that, in general, elements of a C++ Standard Library container can be modified concurrently, but specifically notes
that this is not true for std::vector< bool >.
Note: other C++ Standard Library containers do not have specializations for bool and do not exhibit the behaviours
identified above.
Example
struct myBool { bool b; }; // Wrapper for bool
void foo() noexcept
{
std::vector< bool > a; // Non-compliant - optimized storage
std::vector< std::uint8_t > b; // Compliant
std::vector< myBool > c; // Compliant
std::array < bool, 20 > d; // Rule does not apply
std::bitset< 200 > e; // Rule does not apply - efficient storage
}
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