CERT.OOP.CSTD_FUNC_USE
Prefer special member functions and overloaded operators to C Standard Library functions.
Prefer special member functions and overloaded operators to C Standard Library functions. These C functions includes: memset(), memcpy(), memmove(), strcpy(), memcmp(), strcmp(). You should use C++ equivalent functionality to replace them.
Vulnerability and risk
Several C standard library functions perform bytewise operations on objects. For instance, std::memcmp() compares the bytes comprising the object representation of two objects, and std::memcpy() copies the bytes comprising an object representation into a destination buffer. However, for some object types, it results in undefined or abnormal program behavior.
Mitigation and prevention
You should use C++ equivalent functionality to replace them. For example, to use the class constructor or overloaded operators such as operator<(), operator>(), operator==(), or operator!=().
Example
1 #include <cstring>
2 #include <iostream>
3
4 class C {
5 int scalingFactor;
6 int otherData;
7
8 public:
9 C() : scalingFactor(1) {}
10
11 void set_other_data(int i);
12 int f(int i) {
13 return i / scalingFactor;
14 }
15 // ...
16 };
17
18 void f() {
19 C c;
20
21 // ... Code that mutates c ...
22
23 // Reinitialize c to its default state
24 std::memset(&c, 0, sizeof(C)); //uncompliant code
25
26 std::cout << c.f(100) << std::endl;
27 }
