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Add note on str being an unsized type in strings section of book.

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Alejandro Wainzinger 2016-03-25 23:25:40 +09:00
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6
src/doc/book/strings.md
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@ -44,6 +44,11 @@ let s = "foo\
assert_eq!("foobar", s);
```
Note that you normally cannot access a `str` directly, but only through a `&str`
reference. This is because `str` is an unsized type which requires additional
runtime information to be usable. For more information see the chapter on
[unsized types][ut].
Rust has more than only `&str`s though. A `String` is a heap-allocated string.
This string is growable, and is also guaranteed to be UTF-8. `String`s are
commonly created by converting from a string slice using the `to_string`
@ -185,5 +190,6 @@ let hello_world = hello + &world;
This is because `&String` can automatically coerce to a `&str`. This is a
feature called ‘[`Deref` coercions][dc]’.
[ut]: unsized-types.html
[dc]: deref-coercions.html
[connect]: ../std/net/struct.TcpStream.html#method.connect