CWARN.COPY.NOASSIGN
Class defines copy constructor, but no assignment operator
The CWARN.COPY.NOASSIGN checker finds classes that define a copy constructor, but no assignment operator.
Vulnerability and risk
The default copy constructor and assignment operator generated by the C++ compiler perform a bit-wise copy of class data members. If members are overwritten, memory might not be disposed of properly. This situation can lead to leaked memory and unreleased resources.
Mitigation and prevention
To address the problem, always provide an explicit implementation of the assignment operator for classes that contain dynamically allocated data members, and always ensure that there is a deep copy of those data members.
Vulnerable and fixed code example
class A
{
public:
A(const A &other);
};
class B
{
public:
B(const B &other);
B &operator=(const B &other);
};
class C
{
public:
void f() {}
};In this code example, Klocwork flags class A, since it defines a copy constructor and no assignment operator. In contrast, class B defines both a copy constructor and an assignment operator, and doesn't get flagged.