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ATOMIC_FLAG_INIT

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Revision as of 13:52, 22 March 2014 by Cubbi (Talk | contribs)

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Defined in header <atomic>
#define ATOMIC_FLAG_INIT /* implementation-defined */

Defines the expression which can be used to initialize std::atomic_flag to clear (false) state with the statement std::atomic_flag v = ATOMIC_FLAG_INIT;. It is unspecified if it can be used with other initialization contexts.

If the flag has static storage duration, this initialization is static.

This is the only way to initialize std::atomic_flag to a definite value: the value held after any other initialization is unspecified.

[edit] Example

#include <atomic>
 
std::atomic_flag static_flag = ATOMIC_FLAG_INIT; // static initialization,
// guaranteed to be available during dynamic initialization of static objects.
 
int main()
{
    std::atomic_flag automatic_flag = ATOMIC_FLAG_INIT; // guaranteed to work
//    std::atomic_flag another_flag(ATOMIC_FLAG_INIT); // unspecified
}


[edit] See also

the lock-free boolean atomic type
(class) [edit]