diff --git a/CppCoreGuidelines.md b/CppCoreGuidelines.md
index 375cb08bf..d5cd868ed 100644
--- a/CppCoreGuidelines.md
+++ b/CppCoreGuidelines.md
@@ -1,6 +1,6 @@
# C++ Core Guidelines
-January 3, 2022
+June 13, 2022
Editors:
@@ -2927,31 +2927,11 @@ For advanced uses (only), where you really need to optimize for rvalues passed t
void sink(unique_ptr); // input only, and moves ownership of the widget
-Avoid "esoteric techniques" such as:
-
-* Passing arguments as `T&&` "for efficiency".
- Most rumors about performance advantages from passing by `&&` are false or brittle (but see [F.18](#Rf-consume) and [F.19](#Rf-forward)).
-* Returning `const T&` from assignments and similar operations (see [F.47](#Rf-assignment-op).)
-
-##### Example
-
-Assuming that `Matrix` has move operations (possibly by keeping its elements in a `std::vector`):
-
- Matrix operator+(const Matrix& a, const Matrix& b)
- {
- Matrix res;
- // ... fill res with the sum ...
- return res;
- }
-
- Matrix x = m1 + m2; // move constructor
-
- y = m3 + m3; // move assignment
+Avoid "esoteric techniques" such as passing arguments as `T&&` "for efficiency".
+Most rumors about performance advantages from passing by `&&` are false or brittle (but see [F.18](#Rf-consume) and [F.19](#Rf-forward)).
##### Notes
-The return value optimization doesn't handle the assignment case, but the move assignment does.
-
A reference can be assumed to refer to a valid object (language rule).
There is no (legitimate) "null reference."
If you need the notion of an optional value, use a pointer, `std::optional`, or a special value used to denote "no value."
@@ -3104,6 +3084,26 @@ The argument against is that it prevents (very frequent) use of move semantics.
* If a type is expensive to move (e.g., `array`), consider allocating it on the free store and return a handle (e.g., `unique_ptr`), or passing it in a reference to non-`const` target object to fill (to be used as an out-parameter).
* To reuse an object that carries capacity (e.g., `std::string`, `std::vector`) across multiple calls to the function in an inner loop: [treat it as an in/out parameter and pass by reference](#Rf-out-multi).
+##### Example
+
+Assuming that `Matrix` has move operations (possibly by keeping its elements in a `std::vector`):
+
+ Matrix operator+(const Matrix& a, const Matrix& b)
+ {
+ Matrix res;
+ // ... fill res with the sum ...
+ return res;
+ }
+
+ Matrix x = m1 + m2; // move constructor
+
+ y = m3 + m3; // move assignment
+
+
+##### Note
+
+The return value optimization doesn't handle the assignment case, but the move assignment does.
+
##### Example
struct Package { // exceptional case: expensive-to-move object
@@ -4477,7 +4477,7 @@ For example, a derived class might be allowed to skip a run-time check because i
##### Note
-Prefer the order `public` members before `protected` members before `private` members [see](#Rl-order).
+Prefer the order `public` members before `protected` members before `private` members; see [NL.16](#Rl-order).
##### Enforcement
@@ -8440,7 +8440,7 @@ Many parts of the C++ semantics assume its default meaning.
If you "mess with" operator `&` be sure that its definition has matching meanings for `->`, `[]`, `*`, and `.` on the result type.
Note that operator `.` currently cannot be overloaded so a perfect system is impossible.
-We hope to remedy that: .
+We hope to remedy that: [Operator Dot (R2)](http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4477.pdf).
Note that `std::addressof()` always yields a built-in pointer.
##### Enforcement
@@ -15629,7 +15629,7 @@ Error-handling rule summary:
* [E.13: Never throw while being the direct owner of an object](#Re-never-throw)
* [E.14: Use purpose-designed user-defined types as exceptions (not built-in types)](#Re-exception-types)
* [E.15: Throw by value, catch exceptions from a hierarchy by reference](#Re-exception-ref)
-* [E.16: Destructors, deallocation, and `swap` must never fail](#Re-never-fail)
+* [E.16: Destructors, deallocation, `swap`, and exception type copy/move construction must never fail](#Re-never-fail)
* [E.17: Don't try to catch every exception in every function](#Re-not-always)
* [E.18: Minimize the use of explicit `try`/`catch`](#Re-catch)
* [E.19: Use a `final_action` object to express cleanup if no suitable resource handle is available](#Re-finally)
@@ -16096,11 +16096,11 @@ To rethrow a caught exception use `throw;` not `throw e;`. Using `throw e;` woul
* Flag catching by value of a type that has a virtual function.
* Flag throwing raw pointers.
-### E.16: Destructors, deallocation, and `swap` must never fail
+### E.16: Destructors, deallocation, `swap`, and exception type copy/move construction must never fail
##### Reason
-We don't know how to write reliable programs if a destructor, a swap, or a memory deallocation fails; that is, if it exits by an exception or simply doesn't perform its required action.
+We don't know how to write reliable programs if a destructor, a swap, a memory deallocation, or attempting to copy/move-construct an exception object fails; that is, if it exits by an exception or simply doesn't perform its required action.
##### Example, don't
@@ -16129,14 +16129,17 @@ The standard library assumes that destructors, deallocation functions (e.g., `op
##### Note
-Deallocation functions, including `operator delete`, must be `noexcept`. `swap` functions must be `noexcept`.
-Most destructors are implicitly `noexcept` by default.
-Also, [make move operations `noexcept`](#Rc-move-noexcept).
+* Deallocation functions, including `operator delete`, must be `noexcept`.
+* `swap` functions must be `noexcept`.
+* Most destructors are implicitly `noexcept` by default.
+* Also, [make move operations `noexcept`](#Rc-move-noexcept).
+* If writing a type intended to be used as an exception type, ensure its copy constructor is not `noexcept`. In general we cannot mechanically enforce this, because we do not know whether a type is intended to be used as an exception type.
+* Try not to `throw` a type whose copy constructor is not `noexcept`. In general we cannot mechanically enforce this, because even `throw std::string(...)` could throw but does not in practice.
##### Enforcement
-Catch destructors, deallocation operations, and `swap`s that `throw`.
-Catch such operations that are not `noexcept`.
+* Catch destructors, deallocation operations, and `swap`s that `throw`.
+* Catch such operations that are not `noexcept`.
**See also**: [discussion](#Sd-never-fail)
@@ -20308,6 +20311,14 @@ For writing to a file, there is rarely a need to `flush`.
##### Note
+For string streams (specifically `ostringstream`), the insertion of an `endl` is entirely equivalent
+to the insertion of a `'\n'` character, but also in this case, `endl` might be significantly slower.
+
+`endl` does *not* take care of producing a platform specific end-of-line sequence (like "\r\n" on
+Windows). So for a string stream, `s << endl` just inserts a *single* character, `'\n'`.
+
+##### Note
+
Apart from the (occasionally important) issue of performance,
the choice between `'\n'` and `endl` is almost completely aesthetic.
diff --git a/scripts/hunspell/isocpp.dic b/scripts/hunspell/isocpp.dic
index ef45e4ecd..e9d90e50f 100644
--- a/scripts/hunspell/isocpp.dic
+++ b/scripts/hunspell/isocpp.dic
@@ -389,6 +389,7 @@ optimizable
O'Reilly
org
ostream
+ostringstream
overabstract
overconstrain
overconstrained