Can I use nullptr as a Linux system call parameter?

Question

I'm developing a user space application on Raspbian in C++11. ReSharper++ advises me to use nullptr instead of NULL in the following system call:

auto ret = timerfd_settime(this->_timer_fd, 0, &timeout, NULL);
assert(0 == ret);

I think that I should stay with NULL because this library is dedicated for system programming in C.

What is the best practice in this situation?

Answer 1

Both NULL and nullptr will work fine. However, since this is syspro in C, I would go with NULL , because it's what I see more often (if not always) in that field.

If you check the reference of your system call, you will see that everywhere NULL is mentioned, not nullptr , something which you should expect (if not make sure you 'll read the following answer).

Check also NULL vs nullptr .

Answer 2

I would stay with nullptr because the intention is more clear.

There is a implicit conversion of nullptr to pointer for any type so you are definitely safe.

cppreference.com:

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.