bsls::SpinLock Struct Reference

#include <bsls_spinlock.h>

Detailed Description

A statically-initializable synchronization primitive that "spins" (i.e., executes user instructions in a tight loop) rather than blocking waiting threads using system calls. The following idiom is used to initialize SpinLock variables:

SpinLock lock = BSLS_SPINLOCK_UNLOCKED;

A class member d_lock of type SpinLock may be initialized using the following idiom:

, d_lock(SpinLock::s_unlocked)

See bsls_spinlock

Public Member Functions
void	lock ()
void	lockWithBackoff ()
void	lockWithoutBackoff ()
int	tryLock (int numRetries=0)
void	unlock ()

Public Attributes
AtomicOperations::AtomicTypes::Int	d_state

Static Public Attributes
static const SpinLock	s_unlocked

Member Function Documentation

lock()

void bsls::SpinLock::lock ( )

inline

Spin (repeat a loop continuously without using the system to pause or reschedule the thread) until this object is unlocked, then atomically acquire the lock.

lockWithBackoff()

void bsls::SpinLock::lockWithBackoff ( )

inline

Repeat a loop continuously, potentially using the system to pause or reschedule the thread, until this object is unlocked, then atomically acquire the lock. The spinning has backoff logic.

Note

Note that this method is recommended when system calls are permissible, significant contention is expected, and no better mutual exclusion primitive is available.

lockWithoutBackoff()

void bsls::SpinLock::lockWithoutBackoff ( )

inline

Spin (repeat a loop continuously without using the system to pause or reschedule the thread) until this object is unlocked, then atomically acquire the lock. The spinning does not perform a backoff.

tryLock()

int bsls::SpinLock::tryLock ( int  numRetries = 0 )

inline

Attempt to acquire the lock; optionally specify the numRetries times to attempt again if this object is already locked. Return 0 on success, and a non-zero value if the lock was not successfully acquired.

Precondition

The behavior is undefined unless 0 <= numRetries.

unlock()

void bsls::SpinLock::unlock ( )

inline

Release the lock.

Precondition

The behavior is undefined unless the current thread holds the lock.

Member Data Documentation

d_state

AtomicOperations::AtomicTypes::Int bsls::SpinLock::d_state

0 when unlocked. 'd_state is public to allow aggregate initialization where constexpr constructors are not available. It is semantically private, and should not be used directly.

s_unlocked

const SpinLock bsls::SpinLock::s_unlocked

static

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The documentation for this struct was generated from the following file:

• bsls_spinlock.h