---
name: "std::pmr_monotonic_buffer_resource"
section: "3cxx"
platform: "linux"
package: "libstdc++-13-doc"
version: "13.3.0-16"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/std::pmr_monotonic_buffer_resource/3cxx"
---

# std::pmr\_monotonic\_buffer\_resource(3cxx)

A memory resource that allocates from a fixed-size buffer.

## NAME

std::pmr::monotonic\_buffer\_resource - A memory resource that allocates from a fixed-size buffer.

## SYNOPSIS

`#include <memory_resource>`

Inherits **std::pmr::memory\_resource**.

### Public Member Functions

**monotonic\_buffer\_resource** (const **monotonic\_buffer\_resource** &)=**delete**\
 **monotonic\_buffer\_resource** (**memory\_resource** \***\_\_upstream**) noexcept\
 **monotonic\_buffer\_resource** (size\_t **\_\_initial\_size**) noexcept\
 **monotonic\_buffer\_resource** (size\_t **\_\_initial\_size**, **memory\_resource** \***\_\_upstream**) noexcept\
 **monotonic\_buffer\_resource** (**void** \***\_\_buffer**, size\_t **\_\_buffer\_size**) noexcept\
 **monotonic\_buffer\_resource** (**void** \***\_\_buffer**, size\_t **\_\_buffer\_size**, **memory\_resource** \***\_\_upstream**) noexcept\
 **void** \* **allocate** (size\_t **\_\_bytes**, size\_t **\_\_alignment**=\_S\_max\_align)\
 **void** **deallocate** (**void** \*\_\_p, size\_t **\_\_bytes**, size\_t **\_\_alignment**=\_S\_max\_align)\
 bool **is\_equal** (const **memory\_resource** &\_\_other) const noexcept\
 **monotonic\_buffer\_resource** & **operator=** (const **monotonic\_buffer\_resource** &)=**delete**\
 **void** **release** () noexcept\
 **memory\_resource** \* **upstream\_resource** () const noexcept\

### Protected Member Functions

**void** \* **do\_allocate** (size\_t **\_\_bytes**, size\_t **\_\_alignment**) **override**\
 **void** **do\_deallocate** (**void** \*, size\_t, size\_t) **override**\
 bool **do\_is\_equal** (const **memory\_resource** &\_\_other) const noexcept **override**\

## Detailed Description

A memory resource that allocates from a fixed-size buffer.

The main feature of a `pmr::monotonic_buffer_resource` is that its `do_deallocate` does nothing. This makes it very fast because there is no need to manage a free list, and every allocation simply returns a new block of memory, rather than searching for a suitably-sized free block. Because deallocating is a no-op, the amount of memory used by the resource only grows until `release()` (or the destructor) is called to return all memory to upstream.

A `monotonic_buffer_resource` can be initialized with a buffer that will be used to satisfy all allocation requests, until the buffer is full. After that a new buffer will be allocated from the upstream resource. By using a stack buffer and `pmr::null_memory_resource()` as the upstream you can get a memory resource that only uses the stack and never dynamically allocates.

**Since**

C++17

## Member Function Documentation

### void \* std::pmr::monotonic\_buffer\_resource::do\_allocate (size\_t \_\_bytes, size\_t \_\_alignment)` [inline]`, ` [override]`, ` [protected]`, ` [virtual]`

Implements **std::pmr::memory\_resource**.

### void std::pmr::monotonic\_buffer\_resource::do\_deallocate (void \*, size\_t, size\_t)` [inline]`, ` [override]`, ` [protected]`, ` [virtual]`

Implements **std::pmr::memory\_resource**.

### bool std::pmr::monotonic\_buffer\_resource::do\_is\_equal (const memory\_resource & \_\_other) const` [inline]`, ` [override]`, ` [protected]`, ` [virtual]`, ` [noexcept]`

Implements **std::pmr::memory\_resource**.

## Author

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