sync_per_thread Class
The latest version of this topic can be found at sync_per_thread Class.
Describes a synchronization filter that provides a separate cache object for each thread.
Syntax
template <class Cache>
class sync_per_thread
Parameters
| Parameter | Description |
|---|---|
Cache |
The type of cache associated with the synchronization filter. This can be cache_chunklist, cache_freelist, or cache_suballoc. |
Remarks
Allocators that use sync_per_thread can compare equal even though blocks allocated in one thread cannot be deallocated from another thread. When using one of these allocators memory blocks allocated in one thread should not be made visible to other threads. In practice this means that a container that uses one of these allocators should only be accessed by a single thread.
Member Functions
| allocate | Allocates a block of memory. |
| deallocate | Frees a specified number of objects from storage beginning at a specified position. |
| equals | Compares two caches for equality. |
Requirements
Header: <allocators>
Namespace: stdext
sync_per_thread::allocate
Allocates a block of memory.
void *allocate(std::size_t count);
Parameters
| Parameter | Description |
|---|---|
count |
The number of elements in the array to be allocated. |
Remarks
The member function returns the result of a call to cache::allocate(count) on the cache object belonging to the current thread. If no cache object has been allocated for the current thread, it first allocates one.
sync_per_thread::deallocate
Frees a specified number of objects from storage beginning at a specified position.
void deallocate(void* ptr, std::size_t count);
Parameters
| Parameter | Description |
|---|---|
ptr |
A pointer to the first object to be deallocated from storage. |
count |
The number of objects to be deallocated from storage. |
Remarks
The member function calls deallocate on the cache object belonging to the current thread. If no cache object has been allocated for the current thread, it first allocates one.
sync_per_thread::equals
Compares two caches for equality.
bool equals(const sync<Cache>& Other) const;
Parameters
| Parameter | Description |
|---|---|
Cache |
The cache object of the synchronization filter. |
Other |
The cache object to compare for equality. |
Return Value
false if no cache object has been allocated for this object or for Other in the current thread. Otherwise it returns the result of applying operator== to the two cache objects.