Rule A5-2-3 (required, implementation, automated)
A cast shall not remove any const or volatile qualification from the type of a pointer or reference.
Rationale
Removal of the const or volatile qualification may not meet developer expectations as it may lead to undefined behavior. Note that either const_cast and traditional C-style casts that remove const or volatile qualification shall not be used.
Example
// $Id: A5-2-3.cpp 289436 2017-10-04 10:45:23Z michal.szczepankiewicz $
#include <cstdint>
void F1(const char* str) noexcept(false)
{
*(const_cast<char*>(str)) =
’\0’; // Non-compliant - const qualification removed
}
class C
{
public:
explicit C(std::int32_t) {}
};
void F2() noexcept(false)
{
C const a1 = C(10);
C* a2 = const_cast<C*>(&a1); // Non-compliant - const qualification removed
// Non-compliant - const qualification removed
C* a3 = (C*)&a1;
}
extern volatile std::int32_t* F3() noexcept;
void F4() noexcept
{
volatile std::int32_t* ptr1 = F3();
// ...
std::int32_t* ptr2 = const_cast<std::int32_t*>(
ptr1); // Non-compliant - volatile qualification removed
// ...
std::int32_t* ptr3 =
(std::int32_t*)ptr1; // Non-compliant - volatile qualification removed
}
See also
MISRA C++ 2008 [7]: 5-2-5 A cast shall not remove any const or volatile qualification from the type of a pointer or reference.