I have planty of functions which have std::string as parameter
the string value isn't change inside those functions (I send them as a const)

My question is, should I pass the std::string by value like it was int/double etc
or by reference like I do with structs?

I mean

const std::string myString


should I define func1 like this:
std::string func1(const std::string& myStr)


std::string func1(const std::string myStr)

is std::string is a big structure needs using reference?

thanks a lot