tmp/tmpo_7kdcqb/{from.md → to.md}
RENAMED
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### Operations on atomic types <a id="atomics.types.operations">[[atomics.types.operations]]</a>
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``` cpp
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constexpr atomic() noexcept(is_nothrow_default_constructible_v<T>);
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```
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@@ -49,17 +49,17 @@ type. — *end note*]
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``` cpp
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void store(T desired, memory_order order = memory_order::seq_cst) volatile noexcept;
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void store(T desired, memory_order order = memory_order::seq_cst) noexcept;
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```
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*Preconditions:* The `order` argument is neither
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`memory_order::consume`, `memory_order::acquire`, nor
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`memory_order::acq_rel`.
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*Constraints:* For the `volatile` overload of this function,
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`is_always_lock_free` is `true`.
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*Effects:* Atomically replaces the value pointed to by `this` with the
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value of `desired`. Memory is affected according to the value of
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`order`.
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``` cpp
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``` cpp
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T load(memory_order order = memory_order::seq_cst) const volatile noexcept;
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T load(memory_order order = memory_order::seq_cst) const noexcept;
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```
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*Preconditions:* The `order` argument is neither `memory_order::release`
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nor `memory_order::acq_rel`.
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*Constraints:* For the `volatile` overload of this function,
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`is_always_lock_free` is `true`.
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*Effects:* Memory is affected according to the value of `order`.
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*Returns:* Atomically returns the value pointed to by `this`.
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``` cpp
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@@ -132,16 +132,16 @@ bool compare_exchange_strong(T& expected, T desired,
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memory_order order = memory_order::seq_cst) volatile noexcept;
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bool compare_exchange_strong(T& expected, T desired,
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memory_order order = memory_order::seq_cst) noexcept;
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```
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*Preconditions:* The `failure` argument is neither
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`memory_order::release` nor `memory_order::acq_rel`.
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*Constraints:* For the `volatile` overload of this function,
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`is_always_lock_free` is `true`.
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*Effects:* Retrieves the value in `expected`. It then atomically
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compares the value representation of the value pointed to by `this` for
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equality with that previously retrieved from `expected`, and if true,
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replaces the value pointed to by `this` with that in `desired`. If and
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only if the comparison is `true`, memory is affected according to the
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@@ -161,17 +161,17 @@ Otherwise, these operations are atomic load operations on that memory.
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*Returns:* The result of the comparison.
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[*Note 4*:
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For example, the effect of `compare_exchange_strong` on objects without
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padding bits [[
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``` cpp
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if (memcmp(this, &expected, sizeof(*this)) == 0)
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memcpy(this, &desired, sizeof(*this));
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else
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memcpy(expected, this, sizeof(*this));
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```
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— *end note*]
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[*Example 1*:
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performance on some platforms. When a weak compare-and-exchange would
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require a loop and a strong one would not, the strong one is
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preferable. — *end note*]
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[*Note 6*: Under cases where the `memcpy` and `memcmp` semantics of the
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compare-and-exchange operations apply, the
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`operator==`. — *end note*]
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[*Note 7*:
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Because compare-and-exchange acts on an object’s value representation,
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#### Operations on atomic types <a id="atomics.types.operations">[[atomics.types.operations]]</a>
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``` cpp
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constexpr atomic() noexcept(is_nothrow_default_constructible_v<T>);
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```
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``` cpp
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void store(T desired, memory_order order = memory_order::seq_cst) volatile noexcept;
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void store(T desired, memory_order order = memory_order::seq_cst) noexcept;
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```
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*Constraints:* For the `volatile` overload of this function,
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`is_always_lock_free` is `true`.
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*Preconditions:* The `order` argument is neither
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`memory_order::consume`, `memory_order::acquire`, nor
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`memory_order::acq_rel`.
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*Effects:* Atomically replaces the value pointed to by `this` with the
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value of `desired`. Memory is affected according to the value of
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`order`.
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``` cpp
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``` cpp
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T load(memory_order order = memory_order::seq_cst) const volatile noexcept;
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T load(memory_order order = memory_order::seq_cst) const noexcept;
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```
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*Constraints:* For the `volatile` overload of this function,
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`is_always_lock_free` is `true`.
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*Preconditions:* The `order` argument is neither `memory_order::release`
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nor `memory_order::acq_rel`.
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*Effects:* Memory is affected according to the value of `order`.
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*Returns:* Atomically returns the value pointed to by `this`.
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``` cpp
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memory_order order = memory_order::seq_cst) volatile noexcept;
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bool compare_exchange_strong(T& expected, T desired,
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memory_order order = memory_order::seq_cst) noexcept;
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```
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*Constraints:* For the `volatile` overload of this function,
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`is_always_lock_free` is `true`.
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*Preconditions:* The `failure` argument is neither
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`memory_order::release` nor `memory_order::acq_rel`.
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*Effects:* Retrieves the value in `expected`. It then atomically
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compares the value representation of the value pointed to by `this` for
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equality with that previously retrieved from `expected`, and if true,
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replaces the value pointed to by `this` with that in `desired`. If and
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only if the comparison is `true`, memory is affected according to the
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*Returns:* The result of the comparison.
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[*Note 4*:
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For example, the effect of `compare_exchange_strong` on objects without
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padding bits [[term.padding.bits]] is
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``` cpp
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if (memcmp(this, &expected, sizeof(*this)) == 0)
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memcpy(this, &desired, sizeof(*this));
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else
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memcpy(&expected, this, sizeof(*this));
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```
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— *end note*]
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[*Example 1*:
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performance on some platforms. When a weak compare-and-exchange would
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require a loop and a strong one would not, the strong one is
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preferable. — *end note*]
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[*Note 6*: Under cases where the `memcpy` and `memcmp` semantics of the
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compare-and-exchange operations apply, the comparisons can fail for
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values that compare equal with `operator==` if the value representation
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has trap bits or alternate representations of the same value. Notably,
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on implementations conforming to ISO/IEC/IEEE 60559, floating-point
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`-0.0` and `+0.0` will not compare equal with `memcmp` but will compare
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equal with `operator==`, and NaNs with the same payload will compare
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equal with `memcmp` but will not compare equal with
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`operator==`. — *end note*]
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[*Note 7*:
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Because compare-and-exchange acts on an object’s value representation,
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