Description:

This class is a simple wrapper around C++ standard library type std::shared_timed_mutex. Thus, it is used to implement mutual exclusive access to resources by protecting critical code sections from being executed in parallel in concurrent threads, while allowing typical read-operations to continue to be executed in parallel.
With release-compilations, the only difference to using std::shared_timed_mutex directly is that "spurious wake-ups" are detected and mitigated by this implementation.

When a pair of Acquire and Release invocations is performed within the same code block, then it is recommended to use a stack instantiation of class Owner to acquire and release objects of this class. Such a use is highly simplified with macros ALIB_LOCK and ALIB_LOCK_WITH.
The same is recommended for paired invocations of AcquireShared and ReleaseShared. Here, class OwnerShared is to be used, best using macros ALIB_LOCK_SHARED and ALIB_LOCK_SHARED_WITH.

This class does not allow nested calls to the method Acquire - method Release has to be invoked (from within the same thread that acquired this mutex), before any other thread can again gain access. Nested acquisitions constitute undefined behavior.

Debug-Features

Public member Dbg is available with debug-compilations. It offers the following features:

An assertion is raised when nested use is performed.
The object stores the actual owning thread and the source code position of the last acquirement. Likewise the last shared acquirement's caller information is stored.
Releasing non-acquired instances, as well as destructing acquired one, raises an assertion.
Field WaitTimeLimit the raise of ALib warnings in case a certain wait time is exceeded.
Field DbgWarningMaximumShared enables the raise of ALib warnings in the case that the number of parallel shared acquirements reaches the limit given with this member.

See also

Chapter 3. Locks of the Programmer's Manual of the module ALib Threads.
Chapter A.4 Collecting Caller Information of the General Programmer's Manual.

Definition at line 63 of file sharedtimedlock.hpp.

#include <sharedtimedlock.hpp>

Inheritance diagram for SharedTimedLock:

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Collaboration diagram for SharedTimedLock:

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Public Field Index:
DbgSharedLockAsserter	Dbg
	The debug tool instance.

std::atomic< int >	DbgWarningMaximumShared =10

Public Method Index:
	~SharedTimedLock () override
	Destructor. With debug-compilations, asserts that this lock is not acquired.

ALIB_API void	Acquire (ALIB_DBG_TAKE_CI)

ALIB_API void	AcquireShared (ALIB_DBG_TAKE_CI)

virtual ALIB_API bool	DCSIsAcquired () const override

virtual ALIB_API bool	DCSIsSharedAcquired () const override

ALIB_API void	Release (ALIB_DBG_TAKE_CI)

ALIB_API void	ReleaseShared (ALIB_DBG_TAKE_CI)

ALIB_API bool	TryAcquire (ALIB_DBG_TAKE_CI)

ALIB_API bool	TryAcquireShared (ALIB_DBG_TAKE_CI)

bool	TryAcquireSharedTimed (const Ticks &pointInTime, const CallerInfo &ci)

ALIB_API bool	TryAcquireSharedTimed (const Ticks::Duration &waitDuration, const CallerInfo &ci)

bool	TryAcquireSharedTimed (const Ticks::Duration::TDuration &waitDuration, const CallerInfo &ci)

bool	TryAcquireSharedTimed (const Ticks::TTimePoint &pointInTime, const CallerInfo &ci)

bool	TryAcquireTimed (const Ticks &pointInTime, const CallerInfo &ci)

ALIB_API bool	TryAcquireTimed (const Ticks::Duration &waitDuration, const CallerInfo &ci)

bool	TryAcquireTimed (const Ticks::Duration::TDuration &waitDuration, const CallerInfo &ci)

bool	TryAcquireTimed (const Ticks::TTimePoint &pointInTime, const CallerInfo &ci)

Public Method Index: inherited from DbgCriticalSections::AssociatedLock
virtual	~AssociatedLock ()
	Virtual Destructor.

Protected Field Index:
std::shared_timed_mutex	mutex
	The internal object to lock on.

Field Details:

◆ Dbg

DbgSharedLockAsserter Dbg

The debug tool instance.

Definition at line 75 of file sharedtimedlock.hpp.

◆ DbgWarningMaximumShared

std::atomic<int> DbgWarningMaximumShared =10

Warning-threshold of maximum number of parallel shared acquisitions.
Defaults to 10.

Definition at line 79 of file sharedtimedlock.hpp.

◆ mutex

std::shared_timed_mutex mutex

protected

The internal object to lock on.

Definition at line 70 of file sharedtimedlock.hpp.

Constructor(s) / Destructor Details:

◆ ~SharedTimedLock()

~SharedTimedLock ( )

inlineoverride

Destructor. With debug-compilations, asserts that this lock is not acquired.

Definition at line 83 of file sharedtimedlock.hpp.

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Method Details:

◆ Acquire()

void Acquire ( ALIB_DBG_TAKE_CI )

Same as TryAcquireTimed(const Ticks::Duration&, const CallerInfo&) but misses the parameter waitTime. Using this method, the behavior is equivalent to that of sibling type Lock.

Debug Parameter:: Pass macro ALIB_CALLER_PRUNED with invocations.

Definition at line 801 of file locks.cpp.

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◆ AcquireShared()

void AcquireShared ( ALIB_DBG_TAKE_CI )

Same as TryAcquireSharedTimed(const Ticks::Duration&, const CallerInfo&) but misses the parameter waitTime. Using this method, the behavior is equivalent to that of sibling type SharedLock.

Debug Parameter:: Pass macro ALIB_CALLER_PRUNED with invocations.

Definition at line 899 of file locks.cpp.

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◆ DCSIsAcquired()

bool DCSIsAcquired ( ) const

overridevirtual

Returns: true if the lock is acquired (in non-shared mode), false otherwise.

Implements DbgCriticalSections::AssociatedLock.

Definition at line 283 of file locks.cpp.

◆ DCSIsSharedAcquired()

bool DCSIsSharedAcquired ( ) const

overridevirtual

Returns: true if the lock is shared-acquired (by at least any thread). Otherwise, returns false.

Implements DbgCriticalSections::AssociatedLock.

Definition at line 286 of file locks.cpp.

◆ Release()

void Release ( ALIB_DBG_TAKE_CI )

Releases ownership of this object. If this method is invoked on an object that is not acquired, in debug-compilations an assertion is raised. In release compilations, this leads to undefined behavior.

Debug Parameter:: Pass macro ALIB_CALLER_PRUNED with invocations.

Definition at line 868 of file locks.cpp.

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◆ ReleaseShared()

void ReleaseShared ( ALIB_DBG_TAKE_CI )

Releases shared ownership of this object. Invoking this method on an object that is not "shared acquired" by this thread constitutes undefined behavior.
In debug-compilations the overall sum (of any thread) of shared acquirements and releases is counted, and an assertion is raised if more releases than acquisitions are performed.

Debug Parameter:: Pass macro ALIB_CALLER_PRUNED with invocations.

Definition at line 985 of file locks.cpp.

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◆ TryAcquire()

bool TryAcquire ( ALIB_DBG_TAKE_CI )

nodiscard

Tries to acquire this lock. Multiple (nested) successful calls to this method or method Acquire are not supported and lead to undefined behavior.

Debug Parameter:: Pass macro ALIB_CALLER_PRUNED with invocations.

Returns: true if the lock was not acquired by a different thread and thus, this call was successful. false otherwise.

Definition at line 834 of file locks.cpp.

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◆ TryAcquireShared()

bool TryAcquireShared ( ALIB_DBG_TAKE_CI )

nodiscard

Tries to acquire this lock in shared mode. Multiple (nested) calls to this method or method AcquireShared from within the same thread are not supported and lead to undefined behavior.

Debug Parameter:: Pass macro ALIB_CALLER_PRUNED with invocations.

Returns: true if the lock was not acquired by a different thread and thus, this call was successful. false otherwise.

Definition at line 939 of file locks.cpp.

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◆ TryAcquireSharedTimed() [1/4]

bool TryAcquireSharedTimed	(	const Ticks &	pointInTime,
		const CallerInfo &	ci )

inlinenodiscard

Same as overloaded sibling, but expects a point in time rather than an Ticks::Duration.

Parameters

pointInTime	The point in time, when this method stops waiting.
ci	Caller information. Use macro ALIB_COMMA_CALLER_PRUNED with invocations.

Returns: true if the lock was acquired, false if the pointInTime was reached without successful acquisition.

Definition at line 255 of file sharedtimedlock.hpp.

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◆ TryAcquireSharedTimed() [2/4]

bool TryAcquireSharedTimed	(	const Ticks::Duration &	waitDuration,
		const CallerInfo &	ci )

nodiscard

Same as method TryAcquireShared(ALIB_DBG_TAKE_CI), but accepts a maximum wait time as first parameter.

Parameters

waitDuration	The maximum time-span to wait.
ci	Caller information. Use macro ALIB_COMMA_CALLER_PRUNED with invocations.

Returns: true if the lock was acquired, false if the waitDuration expired without successful acquisition

Definition at line 958 of file locks.cpp.

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◆ TryAcquireSharedTimed() [3/4]

bool TryAcquireSharedTimed	(	const Ticks::Duration::TDuration &	waitDuration,
		const CallerInfo &	ci )

inlinenodiscard

Same as overloaded sibling, but expects a C++ standard library duration type rather than an Ticks::Duration.

Parameters

waitDuration	The point in time, when this method stops waiting.
ci	Caller information. Available only with debug-builds.

Returns: true if the lock was acquired, false if the pointInTime was reached without successful acquisition.

Definition at line 244 of file sharedtimedlock.hpp.

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◆ TryAcquireSharedTimed() [4/4]

bool TryAcquireSharedTimed	(	const Ticks::TTimePoint &	pointInTime,
		const CallerInfo &	ci )

inlinenodiscard

Same as overloaded sibling, but expects a C++ standard library point in time type rather than a Ticks::Duration value.

Parameters

pointInTime	The point in time, when this method stops waiting.
ci	Caller information. Use macro ALIB_COMMA_CALLER_PRUNED with invocations.

Returns: true if the lock was acquired, false if the pointInTime was reached without successful acquisition.

Definition at line 267 of file sharedtimedlock.hpp.

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◆ TryAcquireTimed() [1/4]

bool TryAcquireTimed	(	const Ticks &	pointInTime,
		const CallerInfo &	ci )

inlinenodiscard

Same as overloaded sibling, but expects a point in time rather than an Ticks::Duration.

Parameters

pointInTime	The point in time, when this method stops waiting.
ci	Caller information. Use macro ALIB_COMMA_CALLER_PRUNED with invocations.

Returns: true if the lock was acquired, false if the pointInTime was reached without successful acquisition.

Definition at line 159 of file sharedtimedlock.hpp.

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◆ TryAcquireTimed() [2/4]

bool TryAcquireTimed	(	const Ticks::Duration &	waitDuration,
		const CallerInfo &	ci )

nodiscard

A thread which invokes this method gets registered as the current owner of this object, until the same thread releases the ownership invoking Release. In the case that this object is already owned by another thread, the invoking thread is suspended until ownership can be gained. Multiple (nested) calls to this method are not supported and lead to undefined behavior.

Parameters

waitDuration	The maximum time-span to wait.
ci	Caller information. Use macro ALIB_COMMA_CALLER_PRUNED with invocations.

Returns: true if the lock was acquired, false if the waitDuration expired without successful acquisition

Definition at line 847 of file locks.cpp.

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◆ TryAcquireTimed() [3/4]

bool TryAcquireTimed	(	const Ticks::Duration::TDuration &	waitDuration,
		const CallerInfo &	ci )

inlinenodiscard

Same as overloaded sibling, but expects a C++ standard library duration type rather than an Ticks::Duration.

Parameters

waitDuration	The point in time, when this method stops waiting.
ci	Caller information. Use macro ALIB_COMMA_CALLER_PRUNED with invocations.

Returns: true if the lock was acquired, false if the pointInTime was reached without successful acquisition.

Definition at line 148 of file sharedtimedlock.hpp.

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◆ TryAcquireTimed() [4/4]

bool TryAcquireTimed	(	const Ticks::TTimePoint &	pointInTime,
		const CallerInfo &	ci )

inlinenodiscard

Same as overloaded sibling, but expects a C++ standard library point in time type rather than an Ticks::Duration.

Debug Parameter:: Pass macro ALIB_COMMA_CALLER_PRUNED with invocations.

Parameters

pointInTime	The point in time, when this method stops waiting.
ci	Caller information. Use macro ALIB_COMMA_CALLER_PRUNED with invocations.

Returns: true if the lock was acquired, false if the pointInTime was reached without successful acquisition.

Definition at line 173 of file sharedtimedlock.hpp.

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

Description:

Public Field Index:

Public Method Index:

Protected Field Index:

Field Details:

◆ Dbg

◆ DbgWarningMaximumShared

◆ mutex

Constructor(s) / Destructor Details:

◆ ~SharedTimedLock()

Method Details:

◆ Acquire()

◆ AcquireShared()

◆ DCSIsAcquired()

◆ DCSIsSharedAcquired()

◆ Release()

◆ ReleaseShared()

◆ TryAcquire()

◆ TryAcquireShared()

◆ TryAcquireSharedTimed() [1/4]

◆ TryAcquireSharedTimed() [2/4]

◆ TryAcquireSharedTimed() [3/4]

◆ TryAcquireSharedTimed() [4/4]

◆ TryAcquireTimed() [1/4]

◆ TryAcquireTimed() [2/4]

◆ TryAcquireTimed() [3/4]

◆ TryAcquireTimed() [4/4]