Merge 2019-07 LWG Motion 17

P1612R1 Relocate endian’s specification

Fixes #3021.

Author: zygoloid

source/numerics.tex

@@ -1317,6 +1317,13 @@
     constexpr int countr_one(T x) noexcept;
   template<class T>
     constexpr int popcount(T x) noexcept;
+
+  // \ref{bit.endian}, endian
+  enum class endian {
+    little = @\seebelow@,
+    big    = @\seebelow@,
+    native = @\seebelow@
+  };
 }
 \end{codeblock}
 
@@ -1598,6 +1605,42 @@
 The number of \tcode{1} bits in the value of \tcode{x}.
 \end{itemdescr}
 
+\rSec2[bit.endian]{Endian}
+
+\pnum
+Two common methods of byte ordering in multibyte scalar types are big-endian
+and little-endian in the execution environment. Big-endian is a format for
+storage of binary data in which the most significant byte is placed first,
+with the rest in descending order. Little-endian is a format for storage of
+binary data in which the least significant byte is placed first, with the rest
+in ascending order. This subclause describes the endianness of the scalar types
+of the execution environment.
+
+\indexlibrary{\idxcode{endian}}%
+\indexlibrarymember{little}{endian}%
+\indexlibrarymember{big}{endian}%
+\indexlibrarymember{native}{endian}%
+\begin{itemdecl}
+enum class endian {
+  little = @\seebelow@,
+  big    = @\seebelow@,
+  native = @\seebelow@
+};
+\end{itemdecl}
+
+\begin{itemdescr}
+\pnum
+If all scalar types have size 1 byte, then all of \tcode{endian::little},
+\tcode{endian::big}, and \tcode{endian::native} have the same value.
+Otherwise, \tcode{endian::little} is not equal to \tcode{endian::big}.
+If all scalar types are big-endian, \tcode{endian::native} is
+equal to \tcode{endian::big}.
+If all scalar types are little-endian, \tcode{endian::native} is
+equal to \tcode{endian::little}.
+Otherwise, \tcode{endian::native} is not equal
+to either \tcode{endian::big} or \tcode{endian::little}.
+\end{itemdescr}
+
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

source/support.tex

@@ -590,6 +590,8 @@
   \tcode{<new>} \\ \rowsep
 \defnlibxname{cpp_lib_enable_shared_from_this}              & \tcode{201603L} &
   \tcode{<memory>} \\ \rowsep
+\defnlibxname{cpp_lib_endian}                               & \tcode{201907L} &
+  \tcode{<bit>} \\ \rowsep
 \defnlibxname{cpp_lib_erase_if}                             & \tcode{201811L} &
   \tcode{<string>} \tcode{<deque>} \tcode{<forward_list>} \tcode{<list>}
   \tcode{<vector>} \tcode{<map>} \tcode{<set>} \tcode{<unordered_map>}

source/utilities.tex

@@ -16506,13 +16506,6 @@
   template<class... B> struct disjunction;
   template<class B> struct negation;
 
-  // \ref{meta.endian}, endian
-  enum class endian {
-    little = @\seebelow@,
-    big    = @\seebelow@,
-    native = @\seebelow@
-  };
-
   // \ref{meta.unary.cat}, primary type categories
   template<class T>
     inline constexpr bool is_void_v = is_void<T>::value;
@@ -18330,42 +18323,6 @@
 is a \oldconcept{UnaryTypeTrait} with a base characteristic of \tcode{bool_constant<!bool(B::\brk{}value)>}.
 \end{itemdescr}
 
-\rSec2[meta.endian]{Endian}
-
-\pnum
-Two common methods of byte ordering in multibyte scalar types are big-endian
-and little-endian in the execution environment. Big-endian is a format for
-storage of binary data in which the most significant byte is placed first,
-with the rest in descending order. Little-endian is a format for storage of
-binary data in which the least significant byte is placed first, with the rest
-in ascending order. This subclause describes the endianness of the scalar types
-of the execution environment.
-
-\indexlibrary{\idxcode{endian}}%
-\indexlibrarymember{little}{endian}%
-\indexlibrarymember{big}{endian}%
-\indexlibrarymember{native}{endian}%
-\begin{itemdecl}
-enum class endian {
-  little = @\seebelow@,
-  big    = @\seebelow@,
-  native = @\seebelow@
-};
-\end{itemdecl}
-
-\begin{itemdescr}
-\pnum
-If all scalar types have size 1 byte, then all of \tcode{endian::little},
-\tcode{endian::big}, and \tcode{endian::native} have the same value.
-Otherwise, \tcode{endian::little} is not equal to \tcode{endian::big}.
-If all scalar types are big-endian, \tcode{endian::native} is
-equal to \tcode{endian::big}.
-If all scalar types are little-endian, \tcode{endian::native} is
-equal to \tcode{endian::little}.
-Otherwise, \tcode{endian::native} is not equal
-to either \tcode{endian::big} or \tcode{endian::little}.
-\end{itemdescr}
-
 \rSec2[meta.const.eval]{Constant evaluation context}
 \begin{itemdecl}
 constexpr bool is_constant_evaluated() noexcept;