C++ Style: When using c function in c++, should I check for NULL or nullptr?

Question

In a C++ program, if I want to use a c function that will return NULL for any error, should I check for nullptr or NULL?

int * ptr = someCfunction();
if (ptr == nullptr)
    return false;

or:

int * ptr = someCfunction();
if (ptr == NULL)
    return false;

Which one is better in terms of style?

Answer 1

From the cppreference on nullptr, you can see that there is implicit conversion from nullptr to NULL. So you can do either but (as good practice) better use nullptr from C++11 onwards.

The keyword nullptr denotes the pointer literal. It is a prvalue of type std::nullptr_t. There exist implicit conversions from nullptr to null pointer value of any pointer type and any pointer to member type. Similar conversions exist for any null pointer constant, which includes values of type std::nullptr_t as well as the macro NULL.