When to Use

• Optimization: you can carefully review your code and replace various string operations with string_view. In most cases, you should end up with faster code and fewer memory allocations.
• As a possible replacement for const std::string& parameter - especially in functions that don’t need the ownership and don’t store the string.
• Handling strings coming from other API: QString, CString, constchar*… everything that is placed in a contiguous memory chunk and has a basic char-type. You can write a function that accepts string_view and no conversion from that other implementation will happen.

In any case, it’s important to remember that it’s only a non-owning view, so if the original object is gone, the view becomes rubbish and you might get into trouble.

Moreover, string_view might not contain null terminator so your code has to support that as well.

For example, it’s never a good idea to pass string_view to a function that accepts null-terminated​ strings. More on that in a separate section - about Risks with string_view.

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We can see that string_view is a useful tool for performance. However, it is a sub-class of a more generic template class called std::basic_string_view. More on that in the next lesson.