Merge 2018-03 LWG Motion 13

Author: zygoloid

source/iostreams.tex

@@ -2348,6 +2348,10 @@
 
 \rSec3[fmtflags.manip]{\tcode{fmtflags} manipulators}
 
+\pnum
+Each function specified in this subclause
+is a designated addressable function\iref{namespace.std}.
+
 \indexlibrary{\idxcode{boolalpha}}%
 \begin{itemdecl}
 ios_base& boolalpha(ios_base& str);
@@ -2574,6 +2578,10 @@
 
 \rSec3[adjustfield.manip]{\tcode{adjustfield} manipulators}
 
+\pnum
+Each function specified in this subclause
+is a designated addressable function\iref{namespace.std}.
+
 \indexlibrary{\idxcode{internal}}%
 \begin{itemdecl}
 ios_base& internal(ios_base& str);
@@ -2624,6 +2632,10 @@
 
 \rSec3[basefield.manip]{\tcode{basefield} manipulators}
 
+\pnum
+Each function specified in this subclause
+is a designated addressable function\iref{namespace.std}.
+
 \indexlibrary{\idxcode{dec}}%
 \begin{itemdecl}
 ios_base& dec(ios_base& str);
@@ -2682,6 +2694,10 @@
 
 \rSec3[floatfield.manip]{\tcode{floatfield} manipulators}
 
+\pnum
+Each function specified in this subclause
+is a designated addressable function\iref{namespace.std}.
+
 \indexlibrary{\idxcode{fixed}}%
 \begin{itemdecl}
 ios_base& fixed(ios_base& str);
@@ -5526,6 +5542,10 @@
 
 \rSec3[istream.manip]{Standard \tcode{basic_istream} manipulators}
 
+\pnum
+Each instantiation of this function template
+is a designated addressable function\iref{namespace.std}.
+
 \indexlibrary{\idxcode{ws}}%
 \begin{itemdecl}
 template<class charT, class traits>
@@ -6597,6 +6617,11 @@
 
 \rSec3[ostream.manip]{Standard \tcode{basic_ostream} manipulators}
 
+\pnum
+Each instantiation of a function template
+specified in this subclause
+is a designated addressable function\iref{namespace.std}.
+
 \indexlibrary{\idxcode{endl}}%
 \begin{itemdecl}
 template<class charT, class traits>

source/iterators.tex

@@ -3345,6 +3345,8 @@
 headers are included: \tcode{<array>}, \tcode{<deque>}, \tcode{<forward_list>},
 \tcode{<list>}, \tcode{<map>}, \tcode{<regex>}, \tcode{<set>}, \tcode{<string>},
 \tcode{<string_view>}, \tcode{<unordered_map>}, \tcode{<unordered_set>}, and \tcode{<vector>}.
+Each of these templates
+is a designated customization point\iref{namespace.std}.
 
 \indexlibrary{\idxcode{begin(C\&)}}%
 \begin{itemdecl}
@@ -3482,6 +3484,8 @@
 \tcode{<map>}, \tcode{<regex>}, \tcode{<set>}, \tcode{<string>},
 \tcode{<string_view>},
 \tcode{<unordered_map>}, \tcode{<unordered_set>}, and \tcode{<vector>}.
+Each of these templates
+is a designated customization point\iref{namespace.std}.
 
 \indexlibrary{\idxcode{size(C\& c)}}%
 \begin{itemdecl}

source/lib-intro.tex

@@ -2199,17 +2199,23 @@
 \rSec4[namespace.std]{Namespace \tcode{std}}
 
 \pnum
-The behavior of a \Cpp{} program is undefined if it adds declarations or definitions to namespace
+Unless otherwise specified,
+the behavior of a \Cpp{} program is undefined if it adds declarations or definitions to namespace
 \tcode{std}
 or to a namespace within namespace
-\tcode{std}
-unless otherwise specified.
-A program may add a template specialization for any standard library template
+\tcode{std}.
+
+\pnum
+Unless explicitly prohibited,
+a program may add a template specialization for
+any standard library class template
 to namespace
-\tcode{std} only if the declaration
-depends on a user-defined type
-and the specialization meets the standard library requirements
-for the original template and is not explicitly prohibited.\footnote{Any
+\tcode{std} provided that
+(a) the added declaration
+depends on at least one user-defined type
+and
+(b) the specialization meets the standard library requirements
+for the original template.\footnote{Any
 library code that instantiates other library templates
 must be prepared to work adequately with any user-supplied specialization
 that meets the minimum requirements of this document.}
@@ -2234,11 +2240,90 @@
 
 \item a deduction guide for any standard library class template.
 \end{itemize}
-A program may explicitly instantiate a template defined in the standard library
-only if the declaration depends on the name of a user-defined type
-and the instantiation meets the standard library requirements for the
+
+\pnum
+A program may explicitly instantiate
+a class template defined in the standard library
+only if the declaration
+(a) depends on the name of at least one user-defined type
+and
+(b) the instantiation meets the standard library requirements for the
 original template.
 
+\pnum
+Let \tcode{\placeholder{F}} denote
+a standard library function\iref{global.functions},
+a standard library static member function,
+or an instantiation
+of a standard library function template.
+Unless \tcode{\placeholder{F}} is designated
+an \defn{addressable function},
+the behavior of a \Cpp{} program is unspecified (possibly ill-formed)
+if it explicitly or implicitly attempts
+to form a pointer
+to \tcode{\placeholder{F}}.
+\begin{note}
+Possible means of forming such pointers include
+application of the unary \tcode{\&} operator\iref{expr.unary.op},
+\tcode{addressof}\iref{specialized.addressof},
+or
+a function-to-pointer standard conversion\iref{conv.func}.
+\end{note}
+Moreover,
+the behavior of a \Cpp{} program is unspecified (possibly ill-formed)
+if it attempts to form a reference
+to \tcode{\placeholder{F}}
+or
+if it attempts to form a pointer-to-member designating
+either a standard library non-static member function\iref{member.functions}
+or an instantiation of a standard library member function template.
+
+\pnum
+Other than in namespace \tcode{std}
+or in a namespace
+within namespace \tcode{std},
+a program may provide
+an overload for any library function template
+designated as a \defn{customization point},
+provided that
+(a)
+the overload's declaration depends
+on at least one user-defined type
+and
+(b)
+the overload meets the standard library requirements
+for the customization point.%
+\footnote{
+Any library customization point
+must be prepared
+to work adequately
+with any user-defined overload
+that meets the minimum requirements
+of this document.
+Therefore
+an implementation may elect,
+under the as-if rule\iref{intro.execution},
+to provide any customization point
+in the form
+of an instantiated function object\iref{function.objects}
+even though the customization point's specification
+is in the form
+of a function template.
+The template parameters
+of each such function object
+and the function parameters
+and return type
+of the object's \tcode{operator()}
+must match those
+of the corresponding customization point's specification.}
+\begin{note}
+This permits
+a (qualified or unqualified) call
+to the customization point
+to invoke the most appropriate overload
+for the given arguments.
+\end{note}
+
 \pnum
 A translation unit shall not declare namespace \tcode{std} to be an inline namespace\iref{namespace.def}.
 

source/std.tex

@@ -74,7 +74,7 @@
 
 %%--------------------------------------------------
 %% add special hyphenation rules
-\hyphenation{tem-plate ex-am-ple in-put-it-er-a-tor name-space name-spaces non-zero}
+\hyphenation{tem-plate ex-am-ple in-put-it-er-a-tor name-space name-spaces non-zero cus-tom-i-za-tion}
 
 %%--------------------------------------------------
 %% turn off all ligatures inside \texttt

source/utilities.tex

@@ -200,7 +200,9 @@
 
 \begin{itemdescr}
 \pnum
-\remarks This function shall not participate in overload resolution
+\remarks This function
+is a designated customization point\iref{namespace.std} and
+shall not participate in overload resolution
 unless \tcode{is_move_constructible_v<T>} is \tcode{true} and
 \tcode{is_move_assignable_v<T>} is \tcode{true}.
 The expression inside \tcode{noexcept} is equivalent to: