[#BloombergLP-bdlma-HeapBypassAllocator]
= xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bdlma.adoc[bdlma]::HeapBypassAllocator
:relfileprefix: ../../
:mrdocs:

Memory allocator that obtains storage directly from virtual memory&period;

== Synopsis

Declared in `&lt;bdlma&lowbar;heapbypassallocator&period;h&gt;`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
class HeapBypassAllocator
    : public xref:BloombergLP/bslma/Allocator.adoc[bslma::Allocator]
----

== Description

This class allows the caller to allocate memory directly from virtual memory, without going through the heap like `malloc` or `new` would&period; 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&period; Thread&hyphen;safe&period;

== Base Classes

[cols="1,4"]
|===
| Name| Description
| `xref:BloombergLP/bslma/Allocator.adoc[bslma::Allocator]`
| Pure abstract protocol for clients and suppliers of raw memory&period;
|===

== Type Aliases

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bslma/Allocator/size_type.adoc[`size&lowbar;type`] 
| Alias for an unsigned integral type capable of representing the number of bytes in this platform&apos;s virtual address space&period;
|===


== Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bdlma/HeapBypassAllocator/2constructor-08.adoc[`HeapBypassAllocator`]         [.small]#[constructor]#
| Constructors
| xref:BloombergLP/bdlma/HeapBypassAllocator/2destructor.adoc[`&#126;HeapBypassAllocator`] [.small]#[destructor]# [.small]#[virtual]#
| Destroy this object, releasing all managed buffers of memory that it has allocated&period;
| xref:BloombergLP/bslma/Allocator/operator_assign.adoc[`operator&equals;`] 
| 
| xref:BloombergLP/bdlma/HeapBypassAllocator/allocate-07.adoc[`allocate`] 
| `allocate` overloads
| xref:BloombergLP/bdlma/HeapBypassAllocator/deallocate-09.adoc[`deallocate`] 
| This method has no effect for this heap bypass allocator&period;
| xref:BloombergLP/bslma/Allocator/deleteObject-09.adoc[`deleteObject`] 
| `deleteObject` overloads
| xref:BloombergLP/bslma/Allocator/deleteObjectRaw-06f.adoc[`deleteObjectRaw`] 
| `deleteObjectRaw` overloads
| xref:BloombergLP/bslma/Allocator/is_equal.adoc[`is&lowbar;equal`] 
| 
|===


== Static Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bslma/Allocator/throwBadAlloc.adoc[`throwBadAlloc`] 
| Throw `std&colon;&colon;bad&lowbar;alloc` or abort the program&period;
|===


== Protected Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bslma/Allocator/do_allocate.adoc[`do&lowbar;allocate`]  [.small]#[virtual]#
| Return a newly allocated block of at least `bytes` with `alignment`&period;
| xref:BloombergLP/bslma/Allocator/do_deallocate.adoc[`do&lowbar;deallocate`]  [.small]#[virtual]#
| Return the memory block at `p` having `bytes` and `alignment`&period;
| xref:BloombergLP/bslma/Allocator/do_is_equal.adoc[`do&lowbar;is&lowbar;equal`]  [.small]#[virtual]#
| Return whether this allocator can exchange memory with `other`&period;
|===



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