How to allow a std:string parameter to be NULL?

Question

I have a function foo(const std::string& str); that it does crash if you call it using foo(NULL).

What can I do to prevent it from cras

Answer 1

You have a function that accepts a std::string, so provide it an std::string, not a pointer.

foo(std::string());

This will provide the function with an empty string, which is probably what you would have interpreted your null value as anyhow.