From Jason Turner

[class.base.init]

C++11 → C++14 3.9 KB 45 lines
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Archived: C++11 | C++14
Markdown: C++11 | C++14
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  1. tmp/tmpkziqa58r/{from.md → to.md} +27 -13
tmp/tmpkziqa58r/{from.md → to.md} RENAMED
@@ -10,11 +10,11 @@ ctor-initializer:
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  ```
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  ``` bnf
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  mem-initializer-list:
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  mem-initializer '...'ₒₚₜ
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- mem-initializer ',' mem-initializer-list '...'ₒₚₜ
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  ```
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  ``` bnf
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  mem-initializer:
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  mem-initializer-id '(' expression-listₒₚₜ ')'
@@ -112,31 +112,39 @@ full-expression. Any expression in a *mem-initializer* is evaluated as
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  part of the full-expression that performs the initialization. A
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  *mem-initializer* where the *mem-initializer-id* denotes a virtual base
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  class is ignored during execution of a constructor of any class that is
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  not the most derived class.
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- In a non-delegating constructor, if a given non-static data member or
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- base class is not designated by a *mem-initializer-id* (including the
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  case where there is no *mem-initializer-list* because the constructor
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- has no *ctor-initializer*) and the entity is not a virtual base class of
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- an abstract class ([[class.abstract]]), then
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  - if the entity is a non-static data member that has a
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- *brace-or-equal-initializer*, the entity is initialized as specified
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- in  [[dcl.init]];
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- - otherwise, if the entity is a variant member ([[class.union]]), no
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- initialization is performed;
 
 
 
 
 
 
 
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  - otherwise, the entity is default-initialized ([[dcl.init]]).
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  An abstract class ([[class.abstract]]) is never a most derived class,
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  thus its constructors never initialize virtual base classes, therefore
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  the corresponding *mem-initializer*s may be omitted. An attempt to
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  initialize more than one non-static data member of a union renders the
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- program ill-formed. After the call to a constructor for class `X` has
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- completed, if a member of `X` is neither initialized nor given a value
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- during execution of the *compound-statement* of the body of the
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- constructor, the member has indeterminate value.
 
 
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  ``` cpp
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  struct A {
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  A();
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  };
@@ -169,10 +177,16 @@ struct A {
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  the `A(int)` constructor will simply initialize `i` to the value of
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  `arg`, and the side effects in `i`’s *brace-or-equal-initializer* will
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  not take place.
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  In a non-delegating constructor, initialization proceeds in the
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  following order:
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  - First, and only for the constructor of the most derived class (
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  [[intro.object]]), virtual base classes are initialized in the order
 
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  ```
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  ``` bnf
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  mem-initializer-list:
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  mem-initializer '...'ₒₚₜ
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+ mem-initializer '...'ₒₚₜ ',' mem-initializer-list
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  ```
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  ``` bnf
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  mem-initializer:
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  mem-initializer-id '(' expression-listₒₚₜ ')'
 
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  part of the full-expression that performs the initialization. A
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  *mem-initializer* where the *mem-initializer-id* denotes a virtual base
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  class is ignored during execution of a constructor of any class that is
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  not the most derived class.
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+ In a non-delegating constructor, if a given potentially constructed
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+ subobject is not designated by a *mem-initializer-id* (including the
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  case where there is no *mem-initializer-list* because the constructor
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+ has no *ctor-initializer*), then
 
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  - if the entity is a non-static data member that has a
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+ *brace-or-equal-initializer* and either
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+ - the constructor’s class is a union ([[class.union]]), and no other
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+ variant member of that union is designated by a *mem-initializer-id*
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+ or
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+ - the constructor’s class is not a union, and, if the entity is a
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+ member of an anonymous union, no other member of that union is
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+ designated by a *mem-initializer-id*,
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+
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+ the entity is initialized as specified in  [[dcl.init]];
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+ - otherwise, if the entity is an anonymous union or a variant member (
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+ [[class.union]]), no initialization is performed;
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  - otherwise, the entity is default-initialized ([[dcl.init]]).
135
 
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  An abstract class ([[class.abstract]]) is never a most derived class,
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  thus its constructors never initialize virtual base classes, therefore
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  the corresponding *mem-initializer*s may be omitted. An attempt to
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  initialize more than one non-static data member of a union renders the
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+ program ill-formed. After the call to a constructor for class `X` for an
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+ object with automatic or dynamic storage duration has completed, if the
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+ constructor was not invoked as part of value-initialization and a member
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+ of `X` is neither initialized nor given a value during execution of the
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+ *compound-statement* of the body of the constructor, the member has an
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+ indeterminate value.
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  ``` cpp
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  struct A {
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  A();
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  };
 
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  the `A(int)` constructor will simply initialize `i` to the value of
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  `arg`, and the side effects in `i`’s *brace-or-equal-initializer* will
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  not take place.
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+ In a non-delegating constructor, the destructor for each potentially
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+ constructed subobject of class type is potentially invoked (
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+ [[class.dtor]]). This provision ensures that destructors can be called
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+ for fully-constructed sub-objects in case an exception is thrown (
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+ [[except.ctor]]).
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+
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  In a non-delegating constructor, initialization proceeds in the
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  following order:
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  - First, and only for the constructor of the most derived class (
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  [[intro.object]]), virtual base classes are initialized in the order