Intel(R) Threading Building Blocks Doxygen Documentation  version 4.2.3
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 40 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 47 of file spin_mutex.h.

47  : flag(0) {
48 #if TBB_USE_THREADING_TOOLS
50 #endif
51  }
void __TBB_EXPORTED_METHOD internal_construct()
Internal constructor with ITT instrumentation.
Definition: spin_mutex.cpp:54
__TBB_atomic_flag flag
0 if lock is released, 1 if lock is acquired.
Definition: spin_mutex.h:42

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 54 of file spin_mutex.cpp.

54  {
55  ITT_SYNC_CREATE(this, _T("tbb::spin_mutex"), _T(""));
56 }
#define ITT_SYNC_CREATE(obj, type, name)
Definition: itt_notify.h:123
#define _T(string_literal)
Standard Windows style macro to markup the string literals.
Definition: itt_notify.h:66

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 148 of file spin_mutex.h.

148  {
149 #if TBB_USE_THREADING_TOOLS
150  aligned_space<scoped_lock> tmp;
151  new(tmp.begin()) scoped_lock(*this);
152 #else
154 #endif /* TBB_USE_THREADING_TOOLS*/
155  }
friend class scoped_lock
Definition: spin_mutex.h:180
__TBB_Flag __TBB_LockByte(__TBB_atomic_flag &flag)
Definition: tbb_machine.h:923
__TBB_atomic_flag flag
0 if lock is released, 1 if lock is acquired.
Definition: spin_mutex.h:42

References __TBB_LockByte(), tbb::aligned_space< T, N >::begin(), 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 159 of file spin_mutex.h.

159  {
160 #if TBB_USE_THREADING_TOOLS
161  aligned_space<scoped_lock> tmp;
162  return (new(tmp.begin()) scoped_lock)->internal_try_acquire(*this);
163 #else
164  return __TBB_TryLockByte(flag);
165 #endif /* TBB_USE_THREADING_TOOLS*/
166  }
bool __TBB_TryLockByte(__TBB_atomic_flag &flag)
Definition: tbb_machine.h:917
friend class scoped_lock
Definition: spin_mutex.h:180
__TBB_atomic_flag flag
0 if lock is released, 1 if lock is acquired.
Definition: spin_mutex.h:42

References __TBB_TryLockByte(), tbb::aligned_space< T, N >::begin(), and flag.

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◆ unlock()

void tbb::spin_mutex::unlock ( )
inline

Release lock.

Definition at line 169 of file spin_mutex.h.

169  {
170 #if TBB_USE_THREADING_TOOLS
171  aligned_space<scoped_lock> tmp;
172  scoped_lock& s = *tmp.begin();
173  s.my_mutex = this;
174  s.internal_release();
175 #else
177 #endif /* TBB_USE_THREADING_TOOLS */
178  }
#define __TBB_UnlockByte
Definition: gcc_generic.h:215
friend class scoped_lock
Definition: spin_mutex.h:180
void const char const char int ITT_FORMAT __itt_group_sync s
__TBB_atomic_flag flag
0 if lock is released, 1 if lock is acquired.
Definition: spin_mutex.h:42

References __TBB_UnlockByte, tbb::aligned_space< T, N >::begin(), flag, and s.

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Friends And Related Function Documentation

◆ scoped_lock

friend class scoped_lock
friend

Definition at line 180 of file spin_mutex.h.

Referenced by lock().

Member Data Documentation

◆ flag

◆ is_fair_mutex

const bool tbb::spin_mutex::is_fair_mutex = false
static

Definition at line 143 of file spin_mutex.h.

◆ is_recursive_mutex

const bool tbb::spin_mutex::is_recursive_mutex = false
static

Definition at line 142 of file spin_mutex.h.

◆ is_rw_mutex

const bool tbb::spin_mutex::is_rw_mutex = false
static

Definition at line 141 of file spin_mutex.h.


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

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