string_view: A Reference Type for Strings

As suggested in the C Library Fundamentals TS (N3921) and implemented in C 17, string_view is a type that provides a "view" of a string-like container. Essentially, it allows for efficient handling of strings without the overhead of copying or allocating memory.

Addressing Questions:

1. Is string_view a "string concept"?

Yes, string_view represents a "concept" or abstract view of a string. It can operate on any type of container containing a sequence of characters interpretable as a string.

2. Should canonical const std::string& parameter types become string_view?

Yes, in many cases where a non-mutating view of a string is required, using string_view as a parameter type instead of const std::string& can significantly improve efficiency by avoiding unnecessary copying and allocation.

3. Other Important Points:

• Ownership Semantics: Unlike other C library types, string_view does not own the underlying string data. It is a "referential view" that references an existing string, which can have implications on its lifetime and validity.
• Potential Memory Savings: By using a reference-based approach, string_view eliminates the need for multiple copies of the same string. This can lead to significant memory optimizations in applications working with large amounts of string data.
• Substringing Operations: string_view supports efficient substringing operations, which can be implemented using simple pointer and size adjustments without the overhead of creating a new copy of the substring.
• Limitations: It's important to note that string_view does not allow modification of the underlying string, as it is intended solely for non-mutating operations.

In summary, string_view is a valuable addition to the C standard library, providing a lightweight and efficient way to handle strings. Its use as a reference-based view avoids the overhead of copying and allocation, making it particularly beneficial in performance-sensitive applications. However, it's crucial to understand its unique ownership semantics to ensure correct and reliable usage.