Expand in-place tags page

docs/standard-library/in-place-t-struct-in-place-type-t-struct-in-place-index-t-struct.md

@@ -0,0 +1,36 @@
+---
+description: "Learn more about: in_place_t Struct, in_place_type_t Struct, in_place_index_t Struct"
+title: "in_place_t Struct, in_place_type_t Struct, in_place_index_t Struct"
+ms.date: "11/04/2016"
+f1_keywords: ["utility<in_place_t>", "utility/std::in_place_t", "utility<in_place_type_t>", "utility/std::in_place_type_t", "utility<in_place_index_t>", "utility/std::in_place_index_t"]
+helpviewer_keywords: ["utility<in_place_t> struct"]
+---
+# in_place_t Struct, in_place_type_t Struct, in_place_index_t Struct
+
+The empty structure type `in_place_t` can be passed into constructors of `expected` class, [`optional` class](optional-class.md) or [`single_view` class](single-view-class.md) for in-place construction of the contained type. The empty structure type `in_place_type_t` can be passed into constructors of [`any` class](any-class.md) or [`variant` class](variant-class.md) to specify the type of the object. The empty structure type `in_place_index_t` can be passed into constructors of [`variant` class](variant-class.md) to specify the index of the object.
+
+## Syntax
+
+```cpp
+struct in_place_t {
+    explicit in_place_t() = default;
+};
+
+inline constexpr in_place_t in_place{};
+
+template <class T>
+struct in_place_type_t {
+    explicit in_place_type_t() = default;
+};
+
+template <class T>
+inline constexpr in_place_type_t<T> in_place_type{};
+
+template <size_t I>
+struct in_place_index_t {
+    explicit in_place_index_t() = default;
+};
+
+template <size_t I>
+inline constexpr in_place_index_t<I> in_place_index{};
+```

docs/standard-library/optional-class.md

@@ -11,7 +11,7 @@ The class template `optional<T>` describes an object that may or may not contain
 
 When an instance of `optional<T>` contains a value, the contained value is allocated within the storage of the `optional` object, in a region suitably aligned for type `T`. When an `optional<T>` is converted to **`bool`**, the result is **`true`** if the object contains a value; otherwise, it's **`false`**.
 
-The contained object type `T` must not be [in_place_t](in-place-t-struct.md) or [nullopt_t](nullopt-t-structure.md). `T` must be *destructible*, that is, its destructor must reclaim all owned resources, and may throw no exceptions.
+The contained object type `T` must not be [in_place_t](in-place-t-struct-in-place-type-t-struct-in-place-index-t-struct.md) or [nullopt_t](nullopt-t-structure.md). `T` must be *destructible*, that is, its destructor must reclaim all owned resources, and may throw no exceptions.
 
 The `optional` class is new in C++17.
 

docs/standard-library/utility.md

@@ -75,7 +75,7 @@ Pairs are widely used in the C++ Standard Library. They are required both as the
 |-|-|
 |[from_chars_result](../standard-library/from-chars-result-structure.md)|A struct used for `from_chars`.|
 |[identity](../standard-library/identity-structure.md)|A struct that provides a type definition as the template parameter.|
-|[in_place_t](../standard-library/in-place-t-struct.md)|Also includes structs `in_place_type_t` and `in_place_index_t`.|
+|[in_place_t, in_place_type_t, in_place_index_t](../standard-library/in-place-t-struct-in-place-type-t-struct-in-place-index-t-struct.md)|Types used to control in-place construction.|
 |[integer_sequence](../standard-library/integer-sequence-class.md)|Represents an integer sequence.|
 |[pair](../standard-library/pair-structure.md)|A type that provides for the ability to treat two objects as a single object.|
 |[piecewise_construct_t](../standard-library/piecewise-construct-t-structure.md)|A type used to keep separate constructor and function overloading.|