function
<atomic>
std::atomic_compare_exchange_weak_explicit
| template (1) |
template <class T>
bool atomic_compare_exchange_weak_explicit (volatile atomic<T>* obj,
T* expected, T val, memory_order success, memory_order failure) noexcept;
template <class T>
bool atomic_compare_exchange_weak_explicit (atomic<T>* obj,
T* expected, T val, memory_order success, memory_order failure) noexcept;
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| overloads (2) |
bool atomic_compare_exchange_weak_explicit (volatile A* obj,
T* expected, T val, memory_order success, memory_order failure) noexcept;
bool atomic_compare_exchange_weak_explicit (A* obj,
T* expected, T val, memory_order success, memory_order failure) noexcept; |
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Compare and exchange contained value (weak, explicit)
Parameters
- obj
- Pointer to an atomic object.
Type A represents other overloaded atomic types (if the library does not implement the C-style atomic types as instantiations of atomic).
- expected
- Pointer to an object whose value is compared to the contained value, and which -in case it doesn't match- may be overwritten with the contained value.
T is the type of the value contained in the atomic object (atomic's template parameter).
- val
- Value to copy to the contained object in case expected matches the contained value.
T is the type of the value contained in the atomic object (atomic's template parameter).
- success
- Synchronization mode for the operation in case expected matches the contained value.
This shall be a value of the enum type memory_order.
- failure
- Synchronization mode for the operation in case expected does not match the contained value.
This shall be a value of the enum type memory_order that is neither memory_order_release nor memory_order_acq_rel, and which is not stronger than success.
Return value
true if *expected compares equal to the contained value (and does not fail spuriously).
false otherwise.
Data races
No data races (atomic operation). Memory order specified by arguments success and failure.
Exception safety
No-throw guarantee: never throws exceptions.