BloombergLP::bslma::Allocator

Name

Description

std::pmr::memory_resource

Name

Description

size_type

Alias for an unsigned integral type capable of representing the number of bytes in this platform's virtual address space.

Name

Description

~Allocator [destructor] [virtual]

Destroy this allocator. Note that the behavior of destroying an allocator while memory is allocated from it is not specified; unless you know that it is valid to do so, don't!

operator=

allocate

Return a newly allocated block of memory of the specified size bytes.

deallocate

Return the memory block at the specified address to this allocator.

deleteObject

deleteObject overloads

deleteObjectRaw

deleteObjectRaw overloads

is_equal

Name

Description

throwBadAlloc

Throw std::bad_alloc if exceptions are enabled or abort the program otherwise. Derived classes and helper functions will typically call this function when they are unable to satisfy an allocation request. This function never returns.

Name

Description

do_allocate [virtual]

Return a newly allocated block of memory of (at least) the specified positive bytes and having at least the specified alignment. Unless overriden in a derived class, the return value is this‐>allocate(bytes). If this allocator cannot return the requested number of bytes or cannot satisfy the alignment request, then it will throw a std::bad_alloc exception in an exception‐enabled build, or else will abort the program in a non‐exception build. Unless overriden in a derived class, this function will forward the allocation request to the allocate virtual function, padding bytes and adjusting the return value as necessary to ensure sufficient alignment. Note that if bytes is 0, the same non‐null value will be returned every time.

do_deallocate [virtual]

Return the memory block at the specified p address, having the specified bytes and specified alignment, back to this allocator. Unless overriden in a derived class, this function will forward the deallocation request to the deallocate virtual function, padding bytes and adjusting p as necessary to account for alignment values other than the natural alignment for an object of size bytes. The behavior is undefined unless address is a block allocated from this allocator object using the same bytes and alignment and not already deallocated.

do_is_equal [virtual]

Return true if this allocator is equal to the specified other allocator, meaning (at least) that a memory block allocated by one can be deallocated by the other; otherwise return false. Unless overriden, this method returns this == &other.

Name

Description

AlignedAllocator

This protocol provides a pure abstract interface and contract for clients and suppliers of raw aligned memory. If the requested memory cannot be returned, the contract requires that an std::bad_alloc exception be thrown.

AligningAllocator

This class provides a mechanism that serves as a wrapper around another allocator, passed at construction. The mechanism guarantees that all allocations passed to the underlying allocator will be aligned by the alignment specified at construction.

BufferAllocator

This class provides a concrete buffer allocator that implements the Allocator interface, and allocates memory blocks from a fixed‐size buffer that is supplied by the user at construction. The allocator can supply memory that can be maximally (default) or naturally aligned.

ConcurrentAllocatorAdapter

This class defines an implementation of the bslma::Allocator protocol that "decorates" (wraps) a concrete bslma::Allocator to ensure thread‐safe access to the decorated allocator.

ConcurrentPoolAllocator

This class implements the bslma::Allocator protocol to provide an allocator that manages pooled memory blocks of some uniform size, specified either at construction, or at the first invocation of the allocate method. This allocator maintains an internal linked list of free memory blocks, and dispenses one block for each allocate method invocation. When a memory block is deallocated, it is returned to the free list for potential reuse.

CountingAllocator

This class maintains a count of the total number of allocated bytes. The running byte count is initialized to 0 upon construction, is increased by the allocate method, and may be reset to 0 by the resetNumBytesTotal method. The deallocate method appropriately decrement the byte count. The precise definition of byte count is described in the "Byte Count" section of the component‐level documentation.

CountingAllocator

This class defines a concrete "counting" allocator mechanism that implements the bslma::Allocator protocol, and provides instrumentation to track: (1) the number of bytes currently in use, and (2) the cumulative number of bytes that have ever been allocated. The accumulated statistics are based solely on the number of bytes requested (see allocate).

GuardingAllocator

This class defines a concrete thread‐safe "guarding" allocator mechanism that implements the bslma::Allocator protocol, and adjoins a read/write protected guard page to each block of memory returned by the allocate method. The guard page is placed immediately before or immediately following the block returned from allocate according to the GuardPageLocation enumerator value (optionally) supplied at construction. Note that, unlike many other allocators, an allocator cannot be (optionally) supplied at construction; instead, a system facility is used that allocates blocks of memory in multiples of the system page size. Also note that this allocator is intended for debugging purposes only.

HeapBypassAllocator

This class allows the caller to allocate memory directly from virtual memory, without going through the heap like malloc or new would. Note that the only way to free any memory allocated with this object is to destroy the object, at which point all memory it has allocated is freed. Thread‐safe.

MallocFreeAllocator

This class provides direct access to the system‐supplied (native) global std::malloc and std::free. A static method is provided for obtaining a unique, process wide object of this class, which is valid from the time the method is called until after the program (not just main) exits.

ManagedAllocator

This protocol class extends bslma::Allocator for allocators with the ability to release all memory currently allocated through the protocol back to the memory supplier of the derived concrete allocator object.

ManagedAllocator

Provide a protocol for allocators with the ability to release all memory currently allocated through the protocol back to the memory supplier of the derived concrete allocator object.

NewDeleteAllocator

This class defines a concrete mechanism that adapts the system‐supplied (native) global operator new and operator delete to the Allocator protocol. The class method singleton returns a process‐wide unique object of this class whose lifetime is guaranteed to extend from the first call to singleton until the program terminates. A second class method, allocator, allows for conveniently replacing a "null" allocator with this singleton object. Note that this entire class should generally not be used directly by typical clients (see bslma_default for more information).

TestAllocator

This class defines a concrete "test" allocator mechanism that implements the Allocator protocol, and provides instrumentation to track (1) the number of blocks/bytes currently in use, (2) the maximum number of blocks/bytes that have been outstanding at any one time, and (3) the cumulative number of blocks/bytes that have ever been allocated by this test allocator object. The accumulated statistics are based solely on the number of bytes requested. Additional testing facilities include allocation limits, verbosity modes, status, and automated report printing.