tbb::spin_mutex Class Reference

A lock that occupies a single byte. More...

#include <spin_mutex.h>

Inheritance diagram for tbb::spin_mutex:

Collaboration diagram for tbb::spin_mutex:

Classes
class	scoped_lock
	Represents acquisition of a mutex. More...

Public Member Functions
	spin_mutex ()
	Construct unacquired lock. More...
void __TBB_EXPORTED_METHOD	internal_construct ()
	Internal constructor with ITT instrumentation. More...
void	lock ()
	Acquire lock. More...
bool	try_lock ()
	Try acquiring lock (non-blocking) More...
void	unlock ()
	Release lock. More...

Static Public Attributes
static const bool	is_rw_mutex = false
static const bool	is_recursive_mutex = false
static const bool	is_fair_mutex = false

Private Attributes
__TBB_atomic_flag	flag
	0 if lock is released, 1 if lock is acquired. More...

Friends
class	scoped_lock

Detailed Description

A lock that occupies a single byte.

A spin_mutex is a spin mutex that fits in a single byte. It should be used only for locking short critical sections (typically less than 20 instructions) when fairness is not an issue. If zero-initialized, the mutex is considered unheld.

Definition at line 39 of file spin_mutex.h.

Constructor & Destructor Documentation

spin_mutex()

tbb::spin_mutex::spin_mutex ( )

inline

Construct unacquired lock.

Equivalent to zero-initialization of *this.

Definition at line 46 of file spin_mutex.h.

                 : flag(0) {
#if TBB_USE_THREADING_TOOLS
        internal_construct();
#endif
    }

References internal_construct().

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Member Function Documentation

internal_construct()

void tbb::spin_mutex::internal_construct

(

)

Internal constructor with ITT instrumentation.

Definition at line 50 of file spin_mutex.cpp.

                                    {
    ITT_SYNC_CREATE(this, _T("tbb::spin_mutex"), _T(""));
}

References _T, and ITT_SYNC_CREATE.

Referenced by spin_mutex().

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lock()

void tbb::spin_mutex::lock ( )

inline

Acquire lock.

Definition at line 147 of file spin_mutex.h.

                {
#if TBB_USE_THREADING_TOOLS
        aligned_space<scoped_lock> tmp;
        new(tmp.begin()) scoped_lock(*this);
#else
        __TBB_LockByte(flag);
#endif /* TBB_USE_THREADING_TOOLS*/
    }

References __TBB_LockByte(), flag, and scoped_lock.

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try_lock()

bool tbb::spin_mutex::try_lock ( )

inline

Try acquiring lock (non-blocking)

Return true if lock acquired; false otherwise.

Definition at line 158 of file spin_mutex.h.

                    {
#if TBB_USE_THREADING_TOOLS
        aligned_space<scoped_lock> tmp;
        return (new(tmp.begin()) scoped_lock)->internal_try_acquire(*this);
#else
        return __TBB_TryLockByte(flag);
#endif /* TBB_USE_THREADING_TOOLS*/
    }

References __TBB_TryLockByte(), and flag.

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unlock()

void tbb::spin_mutex::unlock ( )

inline

Release lock.

Definition at line 168 of file spin_mutex.h.

                  {
#if TBB_USE_THREADING_TOOLS
        aligned_space<scoped_lock> tmp;
        scoped_lock& s = *tmp.begin();
        s.my_mutex = this;
        s.internal_release();
#else
        __TBB_UnlockByte(flag);
#endif /* TBB_USE_THREADING_TOOLS */
    }

References __TBB_UnlockByte, flag, and s.

Friends And Related Function Documentation

scoped_lock

friend class scoped_lock

friend

Definition at line 179 of file spin_mutex.h.

Referenced by lock().

Member Data Documentation

flag

__TBB_atomic_flag tbb::spin_mutex::flag

private

0 if lock is released, 1 if lock is acquired.

Definition at line 41 of file spin_mutex.h.

Referenced by tbb::spin_mutex::scoped_lock::acquire(), tbb::spin_mutex::scoped_lock::internal_acquire(), tbb::spin_mutex::scoped_lock::internal_try_acquire(), lock(), tbb::spin_mutex::scoped_lock::release(), tbb::spin_mutex::scoped_lock::scoped_lock(), tbb::spin_mutex::scoped_lock::try_acquire(), try_lock(), unlock(), and tbb::spin_mutex::scoped_lock::~scoped_lock().

is_fair_mutex

const bool tbb::spin_mutex::is_fair_mutex = false

static

Definition at line 142 of file spin_mutex.h.

is_recursive_mutex

const bool tbb::spin_mutex::is_recursive_mutex = false

static

Definition at line 141 of file spin_mutex.h.

is_rw_mutex

const bool tbb::spin_mutex::is_rw_mutex = false

static

Definition at line 140 of file spin_mutex.h.

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The documentation for this class was generated from the following files:

• spin_mutex.h
• spin_mutex.cpp