From Jason Turner

[syserr.errcat]

C++17 → C++20 3.7 KB 46 lines
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Archived: C++17 | C++20
Markdown: C++17 | C++20
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  1. tmp/tmpjlao5yva/{from.md → to.md} +11 -30
tmp/tmpjlao5yva/{from.md → to.md} RENAMED
@@ -1,14 +1,14 @@
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  ### Class `error_category` <a id="syserr.errcat">[[syserr.errcat]]</a>
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- #### Class `error_category` overview <a id="syserr.errcat.overview">[[syserr.errcat.overview]]</a>
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  The class `error_category` serves as a base class for types used to
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  identify the source and encoding of a particular category of error code.
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  Classes may be derived from `error_category` to support categories of
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- errors in addition to those defined in this International Standard. Such
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- classes shall behave as specified in this subclause.
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  [*Note 1*: `error_category` objects are passed by reference, and two
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  such objects are equal if they have the same address. This means that
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  applications using custom `error_category` types should create a single
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  object of each such type. — *end note*]
@@ -26,26 +26,19 @@ namespace std {
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  virtual bool equivalent(int code, const error_condition& condition) const noexcept;
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  virtual bool equivalent(const error_code& code, int condition) const noexcept;
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  virtual string message(int ev) const = 0;
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  bool operator==(const error_category& rhs) const noexcept;
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- bool operator!=(const error_category& rhs) const noexcept;
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- bool operator<(const error_category& rhs) const noexcept;
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  };
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  const error_category& generic_category() noexcept;
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  const error_category& system_category() noexcept;
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  }
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  ```
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- #### Class `error_category` virtual members <a id="syserr.errcat.virtuals">[[syserr.errcat.virtuals]]</a>
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-
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- ``` cpp
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- virtual ~error_category();
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- ```
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-
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- *Effects:* Destroys an object of class `error_category`.
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  ``` cpp
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  virtual const char* name() const noexcept = 0;
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  ```
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@@ -73,40 +66,28 @@ virtual bool equivalent(const error_code& code, int condition) const noexcept;
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  virtual string message(int ev) const = 0;
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  ```
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  *Returns:* A string that describes the error condition denoted by `ev`.
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- #### Class `error_category` non-virtual members <a id="syserr.errcat.nonvirtuals">[[syserr.errcat.nonvirtuals]]</a>
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-
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- ``` cpp
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- constexpr error_category() noexcept;
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- ```
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-
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- *Effects:* Constructs an object of class `error_category`.
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  ``` cpp
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  bool operator==(const error_category& rhs) const noexcept;
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  ```
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  *Returns:* `this == &rhs`.
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  ``` cpp
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- bool operator!=(const error_category& rhs) const noexcept;
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  ```
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- *Returns:* `!(*this == rhs)`.
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- ``` cpp
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- bool operator<(const error_category& rhs) const noexcept;
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- ```
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-
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- *Returns:* `less<const error_category*>()(this, &rhs)`.
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-
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- [*Note 1*: `less` ([[comparisons]]) provides a total ordering for
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- pointers. — *end note*]
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- #### Program defined classes derived from `error_category` <a id="syserr.errcat.derived">[[syserr.errcat.derived]]</a>
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  ``` cpp
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  virtual const char* name() const noexcept = 0;
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  ```
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  ### Class `error_category` <a id="syserr.errcat">[[syserr.errcat]]</a>
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+ #### Overview <a id="syserr.errcat.overview">[[syserr.errcat.overview]]</a>
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  The class `error_category` serves as a base class for types used to
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  identify the source and encoding of a particular category of error code.
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  Classes may be derived from `error_category` to support categories of
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+ errors in addition to those defined in this document. Such classes shall
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+ behave as specified in subclause  [[syserr.errcat]].
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  [*Note 1*: `error_category` objects are passed by reference, and two
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  such objects are equal if they have the same address. This means that
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  applications using custom `error_category` types should create a single
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  object of each such type. — *end note*]
 
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  virtual bool equivalent(int code, const error_condition& condition) const noexcept;
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  virtual bool equivalent(const error_code& code, int condition) const noexcept;
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  virtual string message(int ev) const = 0;
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  bool operator==(const error_category& rhs) const noexcept;
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+ strong_ordering operator<=>(const error_category& rhs) const noexcept;
 
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  };
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  const error_category& generic_category() noexcept;
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  const error_category& system_category() noexcept;
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  }
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  ```
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+ #### Virtual members <a id="syserr.errcat.virtuals">[[syserr.errcat.virtuals]]</a>
 
 
 
 
 
 
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  ``` cpp
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  virtual const char* name() const noexcept = 0;
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  ```
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  virtual string message(int ev) const = 0;
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  ```
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  *Returns:* A string that describes the error condition denoted by `ev`.
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+ #### Non-virtual members <a id="syserr.errcat.nonvirtuals">[[syserr.errcat.nonvirtuals]]</a>
 
 
 
 
 
 
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  ``` cpp
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  bool operator==(const error_category& rhs) const noexcept;
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  ```
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  *Returns:* `this == &rhs`.
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  ``` cpp
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+ strong_ordering operator<=>(const error_category& rhs) const noexcept;
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  ```
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+ *Returns:* `compare_three_way()(this, &rhs)`.
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+ [*Note 1*: `compare_three_way` [[comparisons.three.way]] provides a
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+ total ordering for pointers. — *end note*]
 
 
 
 
 
 
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+ #### Program-defined classes derived from `error_category` <a id="syserr.errcat.derived">[[syserr.errcat.derived]]</a>
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  ``` cpp
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  virtual const char* name() const noexcept = 0;
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  ```
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