Difference between revisions of "cpp/thread/once flag"
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The class {{tt|std::once_flag}} is a helper structure for {{c|std::call_once}}. | The class {{tt|std::once_flag}} is a helper structure for {{c|std::call_once}}. | ||
| − | An object of type {{tt|std::once_flag}} that is passed to multiple calls to {{c|std::call_once}} allows those calls to coordinate with | + | An object of type {{tt|std::once_flag}} that is passed to multiple calls to {{c|std::call_once}} allows those calls to coordinate with each other such that only one of the calls will actually run to completion. |
{{tt|std::once_flag}} is noncopyable. | {{tt|std::once_flag}} is noncopyable. | ||
Revision as of 08:32, 19 November 2012
| Defined in header <mutex>
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| class once_flag; |
(since C++11) | |
The class std::once_flag is a helper structure for std::call_once.
An object of type std::once_flag that is passed to multiple calls to std::call_once allows those calls to coordinate with each other such that only one of the calls will actually run to completion.
std::once_flag is noncopyable.
Contents |
Member functions
std::once_flag::once_flag
| once_flag(); |
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Constructs an once_flag object. The internal state is set to indicate that no function has been called yet.
Parameters
(none)
Exceptions
noexcept specification:
noexcept
