Overview

template<typename GuardedType, typename LockType = pw::sync::VirtualBasicLockable>
class pw::sync::Borrowable< GuardedType, LockType >

The Borrowable is a helper construct that enables callers to borrow an object which is guarded by a lock.

Users who need access to the guarded object can ask to acquire a BorrowedPointer which permits access while the lock is held.

Thread-safety analysis is not supported for this class, as the BorrowedPointers it creates conditionally releases the lock. See also No conditionally held locks.

This class is compatible with locks which comply with BasicLockable C++ named requirement. A try_acquire method is conditionally available if the lock also meets the Lockable requirement. This class is further extended by TimedBorrowable for locks that meet the TimedLockable requirement.

Borrowable<T> is covariant with respect to T, so that Borrowable<U> can be converted to Borrowable<T>, if U is a subclass of T.

Borrowable has pointer-like semantics and should be passed by value.

Inheritance diagram for pw::sync::Borrowable< GuardedType, LockType >:

Public Member Functions
constexpr	Borrowable (GuardedType &object, LockType &lock) noexcept

template<typename U >
constexpr	Borrowable (const Borrowable< U, LockType > &other)

	Borrowable (const Borrowable &)=default

Borrowable &	operator= (const Borrowable &)=default

	Borrowable (Borrowable &&other)=default

Borrowable &	operator= (Borrowable &&other)=default

BorrowedPointer< GuardedType, LockType >	acquire () const
	Blocks indefinitely until the object can be borrowed. Failures are fatal.

template<int &... ExplicitArgumentBarrier, typename T = LockType, typename = std::enable_if_t<is_lockable_v<T>>>
std::optional< BorrowedPointer< GuardedType, LockType > >	try_acquire () const

Friends
template<typename , typename >
class	TimedBorrowable

Member Function Documentation

◆ try_acquire()

template<typename GuardedType , typename LockType = pw::sync::VirtualBasicLockable>

template<int &... ExplicitArgumentBarrier, typename T = LockType, typename = std::enable_if_t<is_lockable_v<T>>>

std::optional< BorrowedPointer< GuardedType, LockType > > pw::sync::Borrowable< GuardedType, LockType >::try_acquire ( ) const

inline

Tries to borrow the object in a non-blocking manner. Returns a BorrowedPointer on success, otherwise std::nullopt (nothing).

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

pw_sync/public/pw_sync/borrow.h

Overview

Public Member Functions

Friends

Member Function Documentation

◆ try_acquire()