LLFIO

https://ned14.github.io/llfio/
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LLFIO v2 is a C++ library providing low-level, asynchronous file I/O operations with support for...
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### Compile Example with Installed Libraries

Source: https://ned14.github.io/llfio/md__build.html

Compile an example C++ file, linking against the installed llfio libraries. Ensure the include path matches your CMAKE_INSTALL_PREFIX.

```cpp
cd example
g++ -std=c++17 -o test map_file.cpp -I/Users/ned/testinstall/inst/include
```

--------------------------------

### Install Dependencies and llfio

Source: https://ned14.github.io/llfio/md__build.html

Install quickcpplib, outcome, and llfio to a specified prefix. This involves cloning each repository, building, and then installing.

```bash
git config --system core.longpaths true
git clone --recursive https://github.com/ned14/quickcpplib.git
cd quickcpplib
mkdir build
cd build
cmake .. -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/usr/local
cmake --build . --parallel
cmake --build . --target install
cd ../..
git clone --recursive https://github.com/ned14/outcome.git
cd outcome
mkdir build
cd build
cmake .. -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/usr/local
cmake --build . --parallel
cmake --build . --target install
cd ../..
git clone --recursive https://github.com/ned14/llfio.git
cd llfio
mkdir build
cd build
cmake .. -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/usr/local
cmake --build . --parallel -- _dl _sl _hl
cmake --build . --target install
cd ../..
```

--------------------------------

### starting_working_directory()

Source: https://ned14.github.io/llfio/namespacemembers_func.html

Gets the starting working directory.

```APIDOC
## starting_working_directory()

### Description
Gets the starting working directory.

### Signature
`starting_working_directory() : llfio_v2_xxx::path_discovery`
```

--------------------------------

### Get starting working directory handle

Source: https://ned14.github.io/llfio/namespacellfio__v2__xxx_1_1path__discovery.html

Returns a handle to the directory that was the working directory at static initialization time, before main() was called. If the directory was unreadable then, a default handle is returned. The result is undefined if the working directory was changed during static initialization.

```cpp
const path_handle & llfio_v2_xxx::path_discovery::starting_working_directory  (  ) 
```

--------------------------------

### begin()

Source: https://ned14.github.io/llfio/classllfio__v2__xxx_1_1path__view.html

Returns a const_iterator pointing to the first path component. This is the starting point for iterating over the components of a path.

```APIDOC
## begin()

### Description
Returns an iterator to the first path component.

### Method
`constexpr const_iterator begin() const noexcept`

### Returns
A `const_iterator` to the beginning of the path components.
```

--------------------------------

### starting_working_directory()

Source: https://ned14.github.io/llfio/namespacemembers.html

Determines the starting working directory. This is a path discovery utility within llfio_v2_xxx::path_discovery.

```APIDOC
## starting_working_directory()

### Description
Determines the starting working directory.

### Signature
`starting_working_directory() : llfio_v2_xxx::path_discovery`
```

--------------------------------

### begin

Source: https://ned14.github.io/llfio/classllfio__v2__xxx_1_1algorithm_1_1trivial__vector-members.html

Returns an iterator to the beginning of the vector. This iterator can be used to traverse the elements from the start.

```APIDOC
## begin

### Description
Returns an iterator pointing to the first element in the vector.

### Overloads
- `begin() noexcept`
- `begin() const noexcept`
```

--------------------------------

### Get file extension with llfio_v2_xxx::path_view_component::extension

Source: https://ned14.github.io/llfio/classllfio__v2__xxx_1_1path__view.html

Returns a view of the file extension. It handles cases where there is no extension, or the extension starts with a dot.

```cpp
constexpr path_view_component llfio_v2_xxx::path_view_component::extension() const noexcept inherited
{
 auto self = _filename();
 return self._invoke(
 [this](const auto &v)
 {
 auto dot_idx = v.rfind('.');
 if(_npos == dot_idx || dot_idx == 0 || (dot_idx == 1 && v[dot_idx - 1] == '.'))
 {
 return path_view_component();
 }
 return path_view_component(v.data() + dot_idx, v.size() - dot_idx, termination());
 });
}
```

--------------------------------

### begin()

Source: https://ned14.github.io/llfio/classllfio__v2__xxx_1_1path__view__component_1_1rendered__path.html

Returns an iterator to the beginning of the path.

```APIDOC
## begin()

### Description
Begin iteration.

### Method
`begin`

### Endpoint
`llfio_v2_xxx::path_view_component::_rendered_path_base_::begin`
```

--------------------------------

### Get mapped file starting offset

Source: https://ned14.github.io/llfio/classllfio__v2__xxx_1_1mapped__file__handle.html

Retrieves the offset into the backing file where this mapped file begins. This is useful for understanding the segment of the file being accessed.

```cpp
551{
  return _offset;
}
```

--------------------------------

### create

Source: https://ned14.github.io/llfio/structkvstore__v1__xxx_1_1basic__key__value__store__info.html

Constructs a store implementation based on the provided URI and configuration options.

```APIDOC
## Function: create

### Description
Construct a store implementation.

### Signature
`result< basic_key_value_store >(* kvstore_v1_xxx::basic_key_value_store_info::create)(const basic_key_value_store::uri_type &uri, size_type key_size, features _features, mode _mode, creation _creation, caching _caching)`
```

--------------------------------

### KVSTORE_V1_NAMESPACE_BEGIN

Source: https://ned14.github.io/llfio/kvstore_8hpp.html

Macro to enter the kv store v1 namespace.

```APIDOC
#define KVSTORE_V1_NAMESPACE_BEGIN

### Description
Expands into the appropriate namespace markup to enter the kv store v1 namespace.
```

--------------------------------

### begin()

Source: https://ned14.github.io/llfio/classllfio__v2__xxx_1_1path__view.html

Returns an iterator to the first path component. This is a non-const member function.

```APIDOC
## begin() [2/2]
| constexpr path_view::iterator llfio_v2_xxx::path_view::begin  | ( | | ) |
---|---|---|---|---
inlineconstexprnoexcept
Returns an iterator to the first path component.
2998{
2999 return cbegin();
3000}
```

--------------------------------

### Functions starting with 'v'

Source: https://ned14.github.io/llfio/functions_func_v.html

Lists functions that start with the letter 'v'.

```APIDOC
## v

### Description
Functions starting with the letter 'v'.

### Functions
- **value()** : `llfio_v2_xxx::error_info`
- **value_size()** : `kvstore_v1_xxx::basic_key_value_store`
```

--------------------------------

### Functions starting with 'd'

Source: https://ned14.github.io/llfio/functions_func_d.html

This section details functions in LLFIO v2.00 that start with the letter 'd'. Each function includes its signature and the classes it belongs to.

```APIDOC
## d

### data()

**Description**: Retrieves data.

**Signature**: `data() : llfio_v2_xxx::algorithm::impl::trivial_vector_impl< has_default_construction, T >, llfio_v2_xxx::byte_io_handle::buffer_type, llfio_v2_xxx::byte_io_handle::const_buffer_type`

### decommit()

**Description**: Decommits memory or resources.

**Signature**: `decommit() : llfio_v2_xxx::map_handle`

### default_metadata()

**Description**: Returns the default metadata.

**Signature**: `default_metadata() : llfio_v2_xxx::algorithm::traversal_summary`

### deleter()

**Description**: Provides a deleter for resource management.

**Signature**: `deleter() : llfio_v2_xxx::path_view_component::rendered_path< ZeroTermination, T, AllocatorOrDeleter, _internal_buffer_size, type >`

### dependencies()

**Description**: Lists dependencies.

**Signature**: `dependencies() : kvstore_v1_xxx::basic_key_value_store::transaction`

### directory()

**Description**: Accesses the directory handle.

**Signature**: `directory() : llfio_v2_xxx::directory_handle`

### directory_handle()

**Description**: Constructs a directory handle.

**Signature**: `directory_handle() : llfio_v2_xxx::directory_handle`

### directory_open_failed()

**Description**: Handles directory open failures.

**Signature**: `directory_open_failed() : llfio_v2_xxx::algorithm::reduce_visitor, llfio_v2_xxx::algorithm::summarize_visitor, llfio_v2_xxx::algorithm::traverse_visitor`

### do_not_store()

**Description**: Indicates that data should not be stored.

**Signature**: `do_not_store() : llfio_v2_xxx::map_handle`

### done()

**Description**: Signals completion.

**Signature**: `done() : llfio_v2_xxx::directory_handle::buffers_type`
```

--------------------------------

### launch_process

Source: https://ned14.github.io/llfio/functions_func_l.html

Launches a new process and returns a handle to it.

```APIDOC
## launch_process()

### Description
Launches a new process.

### Signature
`llfio_v2_xxx::process_handle launch_process()`
```

--------------------------------

### Launch process with default environment

Source: https://ned14.github.io/llfio/classllfio__v2__xxx_1_1process__handle.html

Launches a new process using the provided path, arguments, and flags. It defaults to using the current process's environment. This is a convenience overload.

```cpp
232{
	return launch_process(path, args, *current().environment(), flags);
}
```

--------------------------------

### Get reverse_iterator to before the first element

Source: https://ned14.github.io/llfio/classllfio__v2__xxx_1_1algorithm_1_1trivial__vector.html

Use `rend()` to get a `reverse_iterator` pointing to the element before the first element of the vector. This is typically used in reverse iteration loops.

```cpp
reverse_iterator rend() noexcept
{
  return reverse_iterator(begin());
}
```

--------------------------------

### launch_process

Source: https://ned14.github.io/llfio/classllfio__v2__xxx_1_1process__handle-members.html

Launches a new process with the specified path, arguments, and environment. Optionally waits for the process to close.

```APIDOC
## launch_process

### Description
Launches a new process with the specified path, arguments, and environment. Optionally waits for the process to close.

### Method
static

### Parameters
#### Path Parameters
- **path** (path_view) - Required - The path to the executable.
- **args** (span< path_view_component >) - Required - The arguments for the process.
- **env** (span< path_view_component >) - Optional - The environment variables for the process. Defaults to the current environment.
- **flags** (flag) - Optional - Flags to control process behavior. Defaults to `flag::wait_on_close`.

### Request Example
```cpp
llfio_v2_xxx::process_handle::launch_process(
    "/path/to/executable",
    {"arg1", "arg2"},
    *llfio_v2_xxx::process_handle::current().environment(),
    llfio_v2_xxx::flag::none
);
```

### Response
#### Success Response (process_handle)
Returns a `process_handle` object representing the launched process.
```

```APIDOC
## launch_process

### Description
Launches a new process with the specified path and arguments. Optionally waits for the process to close.

### Method
static inline

### Parameters
#### Path Parameters
- **path** (path_view) - Required - The path to the executable.
- **args** (span< path_view_component >) - Required - The arguments for the process.
- **flags** (flag) - Optional - Flags to control process behavior. Defaults to `flag::wait_on_close`.

### Request Example
```cpp
llfio_v2_xxx::process_handle::launch_process(
    "/path/to/executable",
    {"arg1", "arg2"},
    llfio_v2_xxx::flag::none
);
```

### Response
#### Success Response (process_handle)
Returns a `process_handle` object representing the launched process.
```

--------------------------------

### Get const_reverse_iterator to before the first element

Source: https://ned14.github.io/llfio/classllfio__v2__xxx_1_1algorithm_1_1trivial__vector.html

Use `rend()` to get a `const_reverse_iterator` pointing to the element before the first element of the vector. This is typically used in reverse iteration loops.

```cpp
const_reverse_iterator rend() const noexcept
{
  return const_reverse_iterator(begin());
}
```

--------------------------------

### LLFIO Functions Starting with 'e'

Source: https://ned14.github.io/llfio/functions_func_e.html

This section details functions within the LLFIO library that start with the letter 'e'. Each entry includes the function name and the class it belongs to.

```APIDOC
## Functions starting with 'e'

### emplace()

*   **Description**: Inserts an element into the vector.
*   **Class**: `llfio_v2_xxx::algorithm::impl::trivial_vector_impl< has_default_construction, T >`

### emplace_back()

*   **Description**: Inserts an element at the end of the vector.
*   **Class**: `llfio_v2_xxx::algorithm::impl::trivial_vector_impl< has_default_construction, T >`

### empty()

*   **Description**: Checks if the container is empty.
*   **Classes**: `kvstore_v1_xxx::basic_key_value_store`, `llfio_v2_xxx::algorithm::impl::trivial_vector_impl< has_default_construction, T >`, `llfio_v2_xxx::byte_io_handle::buffer_type`, `llfio_v2_xxx::byte_io_handle::const_buffer_type`, `llfio_v2_xxx::path_view_component`, `llfio_v2_xxx::storage_profile::storage_profile`

### end()

*   **Description**: Returns an iterator to the end of the container.
*   **Classes**: `llfio_v2_xxx::algorithm::impl::trivial_vector_impl< has_default_construction, T >`, `llfio_v2_xxx::byte_io_handle::buffer_type`, `llfio_v2_xxx::byte_io_handle::const_buffer_type`, `llfio_v2_xxx::path_view`, `llfio_v2_xxx::storage_profile::storage_profile`, `llfio_v2_xxx::symlink_handle::buffers_type`, `llfio_v2_xxx::symlink_handle::const_buffers_type`

### entity_from_buffer()

*   **Description**: Creates an entity from a buffer.
*   **Class**: `llfio_v2_xxx::algorithm::shared_fs_mutex::shared_fs_mutex`

### entity_from_string()

*   **Description**: Creates an entity from a string.
*   **Class**: `llfio_v2_xxx::algorithm::shared_fs_mutex::shared_fs_mutex`

### entity_type()

*   **Description**: Gets the type of the entity.
*   **Class**: `llfio_v2_xxx::algorithm::shared_fs_mutex::shared_fs_mutex::entity_type`

### environment()

*   **Description**: Retrieves the environment variables.
*   **Class**: `llfio_v2_xxx::process_handle`

### erase()

*   **Description**: Removes elements from the vector.
*   **Class**: `llfio_v2_xxx::algorithm::impl::trivial_vector_impl< has_default_construction, T >`

### error()

*   **Description**: Returns the error code.
*   **Class**: `llfio_v2_xxx::error`

### error_info()

*   **Description**: Retrieves detailed error information.
*   **Class**: `llfio_v2_xxx::error_info`

### error_pipe()

*   **Description**: Gets the error pipe for the process.
*   **Class**: `llfio_v2_xxx::process_handle`

### exists()

*   **Description**: Checks if a path exists.
*   **Class**: `llfio_v2_xxx::path_handle`

### extension()

*   **Description**: Gets the file extension.
*   **Class**: `llfio_v2_xxx::path_view_component`

### extent()

*   **Description**: Returns the extent of the lock.
*   **Class**: `llfio_v2_xxx::lockable_byte_io_handle::extent_guard`

### extent_guard()

*   **Description**: Constructs an extent guard.
*   **Class**: `llfio_v2_xxx::lockable_byte_io_handle::extent_guard`

### extents()

*   **Description**: Returns the extents of the file.
*   **Classes**: `llfio_v2_xxx::fast_random_file_handle`, `llfio_v2_xxx::file_handle`
```

--------------------------------

### Launch a new process

Source: https://ned14.github.io/llfio/classllfio__v2__xxx_1_1process__handle.html

Creates and launches a new process. Requires an absolute path to the binary. Note that process launching is inherently racy with respect to filesystem modifications.

```cpp
static result< process_handle > launch_process(path_view path,
                                                 span< path_view_component > args,
                                                 span< path_view_component > env= *current().environment(),
                                                 flag flags=flag::wait_on_close) noexcept;
```

--------------------------------

### Functions starting with 'h'

Source: https://ned14.github.io/llfio/functions_func_h.html

This section lists all documented functions in LLFIO v2.00 whose names start with the letter 'h'. It also indicates the classes where these functions are defined or used.

```APIDOC
## Functions starting with 'h'

### Description
This section lists all documented functions in LLFIO v2.00 whose names start with the letter 'h'. It also indicates the classes where these functions are defined or used.

### Functions
- **handle()** : llfio_v2_xxx::algorithm::shared_fs_mutex::atomic_append, llfio_v2_xxx::algorithm::shared_fs_mutex::byte_ranges, llfio_v2_xxx::algorithm::shared_fs_mutex::memory_map< Hasher, HashIndexSize, SpinlockType >, llfio_v2_xxx::handle, llfio_v2_xxx::lockable_byte_io_handle::extent_guard
- **has_extension()** : llfio_v2_xxx::path_view_component
- **has_filename()** : llfio_v2_xxx::path_view
- **has_null_termination()** : llfio_v2_xxx::path_view_component
- **has_parent_path()** : llfio_v2_xxx::path_view
- **has_relative_path()** : llfio_v2_xxx::path_view
- **has_root_directory()** : llfio_v2_xxx::path_view
- **has_root_name()** : llfio_v2_xxx::path_view
- **has_root_path()** : llfio_v2_xxx::path_view
- **has_stem()** : llfio_v2_xxx::path_view_component
```

--------------------------------

### open_kvstore

Source: https://ned14.github.io/llfio/namespacekvstore__v1__xxx.html

Opens an existing key-value store. This is a convenience overload for create_kvstore().

```APIDOC
## open_kvstore

### Description
Open an existing key value store. A convenience overload for `create_kvstore()`.

### Method
result< basic_key_value_store >

### Parameters
- **uri** (const basic_key_value_store::uri_type &) - Required - The URI of the key-value store to open.
- **_mode** (basic_key_value_store::mode) - Optional - The mode to open the store in (defaults to write).
- **_caching** (basic_key_value_store::caching) - Optional - The caching mode (defaults to all).

### Response
#### Success Response
- **basic_key_value_store** - A handle to the opened key-value store.
```

--------------------------------

### temp_directory()

Source: https://ned14.github.io/llfio/namespacemembers_func.html

Gets a temporary directory.

```APIDOC
## temp_directory()

### Description
Gets a temporary directory.

### Signature
`temp_directory() : llfio_v2_xxx`
```

--------------------------------

### kvstore_v1_xxx::open_kvstore

Source: https://ned14.github.io/llfio/kvstore_8hpp.html

Opens an existing key-value store. This is a convenience overload for `create_kvstore()`.

```APIDOC
## open_kvstore

### Description
Open an existing key value store. A convenience overload for `create_kvstore()`.

### Signature
```cpp
result< basic_key_value_store > kvstore_v1_xxx::open_kvstore (
    const basic_key_value_store::uri_type &uri,
    basic_key_value_store::mode _mode = basic_key_value_store::mode::write,
    basic_key_value_store::caching _caching = basic_key_value_store::caching::all
)
```

### Parameters
* **uri** (const basic_key_value_store::uri_type &) - The URI of the key-value store to open.
* **_mode** (basic_key_value_store::mode) - The mode to open the store in (default: write).
* **_caching** (basic_key_value_store::caching) - The caching mode (default: all).
```

--------------------------------

### length

Source: https://ned14.github.io/llfio/namespacemembers_func.html

Gets the length of a file.

```APIDOC
## length()

### Description
Gets the length of a file.

### Namespace
llfio_v2_xxx
```

--------------------------------

### length

Source: https://ned14.github.io/llfio/namespacemembers.html

Gets the length of a resource.

```APIDOC
## length()

### Description
Gets the length of a resource.

### Namespace
llfio_v2_xxx
```

--------------------------------

### begin()

Source: https://ned14.github.io/llfio/structllfio__v2__xxx_1_1algorithm_1_1impl_1_1trivial__vector__impl.html

Returns an iterator to the first element of the container. Overloaded for const and non-const access.

```APIDOC
## begin() [1/2]

### Description
Iterator to the first item.

### Method
`const_iterator begin() const noexcept`

### Return Value
`const_iterator` pointing to the first element.
```

```APIDOC
## begin() [2/2]

### Description
Iterator to the first item.

### Method
`iterator begin() noexcept`

### Return Value
`iterator` pointing to the first element.
```

--------------------------------

### create_kvstore

Source: https://ned14.github.io/llfio/namespacekvstore__v1__xxx.html

Creates a new key-value store, or opens or truncates an existing one, using the provided URI.

```APIDOC
## create_kvstore

### Description
Create a new key value store, or open or truncate an existing key value store, using the given URI.

### Method
result< basic_key_value_store >

### Parameters
- **uri** (const basic_key_value_store::uri_type &) - Required - The URI for the key-value store.
- **key_size** (basic_key_value_store::size_type) - Required - The size of the keys.
- **_features** (basic_key_value_store::features) - Required - The features to enable.
- **_mode** (basic_key_value_store::mode) - Optional - The mode to open the store in (defaults to write).
- **_creation** (basic_key_value_store::creation) - Optional - The creation mode (defaults to if_needed).
- **_caching** (basic_key_value_store::caching) - Optional - The caching mode (defaults to all).

### Response
#### Success Response
- **basic_key_value_store** - A handle to the created or opened key-value store.
```

--------------------------------

### section()

Source: https://ned14.github.io/llfio/namespacemembers_func.html

Gets a section of a file or data.

```APIDOC
## section()

### Description
Gets a section of a file or data.

### Signature
`section() : llfio_v2_xxx`
```

--------------------------------

### starting_working_directory

Source: https://ned14.github.io/llfio/path__discovery_8hpp.html

Returns a reference to an open handle of the verified directory that was the working directory during the process's static data initialization, before main() was invoked.

```APIDOC
## starting_working_directory

### Description
Returns a reference to an open handle to a verified directory which was the working directory during static data init of the process before `main()` was invoked.

### Signature
const path_handle & starting_working_directory () noexcept

### Returns
- **const path_handle &** - A reference to an open handle to the starting working directory.
```

--------------------------------

### page_size

Source: https://ned14.github.io/llfio/namespacemembers_func.html

Gets the page size of a file.

```APIDOC
## page_size()

### Description
Gets the page size of a file.

### Namespace
llfio_v2_xxx::utils
```

--------------------------------

### QUICKCPPLIB_BITFIELD_BEGIN_T for llfio_v2_xxx::handle::mapped_file_handle

Source: https://ned14.github.io/llfio/classllfio__v2__xxx_1_1mapped__file__handle.html

Defines the beginning of a bitfield for flags. The 'none' flag indicates no flags are set.

```cpp
none = uint16_t(0), //!< No flags
```

--------------------------------

### maximum_extent

Source: https://ned14.github.io/llfio/namespacemembers.html

Gets the maximum extent of a resource.

```APIDOC
## maximum_extent()

### Description
Gets the maximum extent of a resource.

### Namespace
llfio_v2_xxx
```

--------------------------------

### begin() [2/2]

Source: https://ned14.github.io/llfio/structllfio__v2__xxx_1_1algorithm_1_1impl_1_1trivial__vector__impl_3_01true_00_01_t_01_4.html

Returns an iterator to the first element.

```APIDOC
## begin() [2/2]
| iterator llfio_v2_xxx::algorithm::impl::trivial_vector_impl< has_default_construction, T >::begin  | ( | | ) |
|---|---|---|---|
inlinenoexceptinherited |
Iterator to first item.
282{ return iterator(_begin); }
```

--------------------------------

### size()

Source: https://ned14.github.io/llfio/classllfio__v2__xxx_1_1path__view__component_1_1rendered__path.html

Get the size of the rendered path.

```APIDOC
## size()

### Description
Size.

### Method
`constexpr size_type size() const`

### Return Value
The size of the rendered path.
```

--------------------------------

### z - Functions

Source: https://ned14.github.io/llfio/functions_func_z.html

Functions starting with the letter 'z'.

```APIDOC
## z - Functions

### Description
Functions starting with the letter 'z'.

### Functions
- **zero()** : llfio_v2_xxx::fast_random_file_handle, llfio_v2_xxx::file_handle, llfio_v2_xxx::mapped_file_handle
  * Description: Returns a file handle representing a zero-filled region.
- **zero_memory()** : llfio_v2_xxx::map_handle
  * Description: Returns a map handle representing a zero-filled memory region.
```

--------------------------------

### llfio_v2_xxx::construct< file_handle >

Source: https://ned14.github.io/llfio/file__handle_8hpp.html

Constructor for file_handle.

```APIDOC
## struct llfio_v2_xxx::construct< file_handle >

### Description
Constructor for `file_handle`.
```

--------------------------------

### starting_offset()

Source: https://ned14.github.io/llfio/classllfio__v2__xxx_1_1mapped__file__handle.html

Retrieves the offset into the backing file from which this mapped file begins.

```APIDOC
## starting_offset()

### Description
The offset into the backing file from which this mapped file begins.

### Method
const

### Endpoint
llfio_v2_xxx::mapped_file_handle::starting_offset()
```

--------------------------------

### starting_offset

Source: https://ned14.github.io/llfio/classllfio__v2__xxx_1_1mapped__file__handle-members.html

Returns the starting offset of the mapped file.

```APIDOC
## starting_offset() const noexcept

### Description
Returns the starting offset of the mapped file.

### Method
`const noexcept`
```

--------------------------------

### create_kvstore

Source: https://ned14.github.io/llfio/namespacemembers_func.html

Creates a new key-value store.

```APIDOC
## create_kvstore()

### Description
Creates a new key-value store.

### Namespace
kvstore_v1_xxx
```

--------------------------------

### temporary_named_pipes_directory()

Source: https://ned14.github.io/llfio/namespacemembers_func.html

Gets the directory for temporary named pipes.

```APIDOC
## temporary_named_pipes_directory()

### Description
Gets the directory for temporary named pipes.

### Signature
`temporary_named_pipes_directory() : llfio_v2_xxx::path_discovery`
```

--------------------------------

### storage_backed_temporary_files_directory()

Source: https://ned14.github.io/llfio/namespacemembers_func.html

Gets the directory for storage-backed temporary files.

```APIDOC
## storage_backed_temporary_files_directory()

### Description
Gets the directory for storage-backed temporary files.

### Signature
`storage_backed_temporary_files_directory() : llfio_v2_xxx::path_discovery`
```

--------------------------------

### KVSTORE V1 Namespace Entry Example

Source: https://ned14.github.io/llfio/group__config.html

Expands into the appropriate namespace markup to enter the kv store v1 namespace. This is typically used at the beginning of a scope that requires access to kv store v1.

```c
#define KVSTORE_V1_NAMESPACE_BEGIN
namespace kvstore_v1_xxx \
{
```

--------------------------------

### page_sizes

Source: https://ned14.github.io/llfio/namespacemembers_func.html

Gets the available page sizes for a file.

```APIDOC
## page_sizes()

### Description
Gets the available page sizes for a file.

### Namespace
llfio_v2_xxx::utils
```

--------------------------------

### KVSTORE_V1_NAMESPACE_EXPORT_BEGIN

Source: https://ned14.github.io/llfio/kvstore_8hpp.html

Macro to enter the exported kv store v1 namespace.

```APIDOC
#define KVSTORE_V1_NAMESPACE_EXPORT_BEGIN

### Description
Expands into the appropriate namespace markup to enter the C++ module exported kv store v1 namespace.
```

--------------------------------

### file_buffer_default_size

Source: https://ned14.github.io/llfio/namespacemembers_func.html

Gets the default buffer size for files.

```APIDOC
## file_buffer_default_size()

### Description
Gets the default buffer size for files.

### Namespace
llfio_v2_xxx::utils
```

--------------------------------

### Opening and Creating Files

Source: https://ned14.github.io/llfio/classllfio__v2__xxx_1_1file__handle.html

These static methods allow users to open existing files or create new ones with specified modes, creation options, caching, and flags.

```APIDOC
## Static Public Member Functions

---

static result< file_handle > | file (const path_handle &base, path_view_type path, mode _mode=mode::read, creation _creation=creation::open_existing, caching _caching=caching::all, flag flags=flag::none) noexcept

---

static result< file_handle > | uniquely_named_file (const path_handle &dirpath, mode _mode=mode::write, caching _caching=caching::temporary, flag flags=flag::none) noexcept

---

static result< file_handle > | temp_file (path_view_type name=path_view_type(), mode _mode=mode::write, creation _creation=creation::if_needed, caching _caching=caching::temporary, flag flags=flag::unlink_on_first_close) noexcept

---

static result< file_handle > | temp_inode (const path_handle &dirh=path_discovery::storage_backed_temporary_files_directory(), mode _mode=mode::write, caching _caching=caching::temporary, flag flags=flag::none) noexcept
```

--------------------------------

### current_process_memory_usage

Source: https://ned14.github.io/llfio/namespacemembers_func.html

Gets the current memory usage of the process.

```APIDOC
## current_process_memory_usage()

### Description
Gets the current memory usage of the process.

### Namespace
llfio_v2_xxx::utils
```

--------------------------------

### begin() [1/2]

Source: https://ned14.github.io/llfio/structllfio__v2__xxx_1_1algorithm_1_1impl_1_1trivial__vector__impl_3_01true_00_01_t_01_4.html

Returns a const iterator to the first element.

```APIDOC
## begin() [1/2]
| const_iterator llfio_v2_xxx::algorithm::impl::trivial_vector_impl< has_default_construction, T >::begin  | ( | | ) |  const  
|---|---|---|---|---|
inlinenoexceptinherited |
Iterator to first item.
284{ return const_iterator(_begin); }
```

--------------------------------

### current_process_cpu_usage

Source: https://ned14.github.io/llfio/namespacemembers_func.html

Gets the current CPU usage of the process.

```APIDOC
## current_process_cpu_usage()

### Description
Gets the current CPU usage of the process.

### Namespace
llfio_v2_xxx::utils
```

--------------------------------

### Create Directory

Source: https://ned14.github.io/llfio/directory__handle_8hpp.html

Creates or opens a directory with specified parameters.

```APIDOC
## directory

### Description
Creates or opens a directory with specified parameters.

### Signature
result< directory_handle > directory(const path_handle &base, directory_handle::path_view_type path, directory_handle::mode _mode=directory_handle::mode::read, directory_handle::creation _creation=directory_handle::creation::open_existing, directory_handle::caching _caching=directory_handle::caching::all, directory_handle::flag flags=directory_handle::flag::none) noexcept
```

--------------------------------

### termination()

Source: https://ned14.github.io/llfio/classllfio__v2__xxx_1_1path__view__component_1_1rendered__path.html

Get the zero termination of this rendered path.

```APIDOC
## termination()

### Description
The zero termination of this rendered path.

### Method
`static constexpr enum termination termination()`

### Return Value
The enum value representing the termination type.
```

--------------------------------

### native_size()

Source: https://ned14.github.io/llfio/classllfio__v2__xxx_1_1path__view__component.html

Gets the size of the path view in characters.

```APIDOC
## native_size()

### Description
Returns the size of the path view in characters.

### Signature
`constexpr size_t llfio_v2_xxx::path_view_component::native_size() const noexcept`

### Return Value
The number of characters in the path view.
```

--------------------------------

### kvstore_v1_xxx::create_kvstore

Source: https://ned14.github.io/llfio/kvstore_8hpp.html

Creates a new key-value store or opens/truncates an existing one using the provided URI and configuration.

```APIDOC
## create_kvstore

### Description
Create a new key value store, or open or truncate an existing key value store, using the given URI.

### Signature
```cpp
template<class T , class... Args>
result< basic_key_value_store > kvstore_v1_xxx::create_kvstore (
    const basic_key_value_store::uri_type &uri,
    basic_key_value_store::size_type key_size,
    basic_key_value_store::features _features,
    basic_key_value_store::mode _mode = basic_key_value_store::mode::write,
    basic_key_value_store::creation _creation = basic_key_value_store::creation::if_needed,
    basic_key_value_store::caching _caching = basic_key_value_store::caching::all
)
```

### Parameters
* **uri** (const basic_key_value_store::uri_type &) - The URI for the key-value store.
* **key_size** (basic_key_value_store::size_type) - The size of the keys.
* **_features** (basic_key_value_store::features) - The features to enable for the store.
* **_mode** (basic_key_value_store::mode) - The mode to open the store in (default: write).
* **_creation** (basic_key_value_store::creation) - The creation mode (default: if_needed).
* **_caching** (basic_key_value_store::caching) - The caching mode (default: all).
```

--------------------------------

### maximum_extent

Source: https://ned14.github.io/llfio/namespacellfio__v2__xxx.html

Gets the maximum extent (size) of a file handle.

```APIDOC
## maximum_extent

### Description
Gets the maximum extent of a file handle.

### Signature
result< file_handle::extent_type > | maximum_extent (const file_handle &self) noexcept
```

--------------------------------

### Construct process_handle using operator()

Source: https://ned14.github.io/llfio/structllfio__v2__xxx_1_1construct_3_01process__handle_01_4.html

This snippet shows the implementation of the operator() for construct< process_handle >, which delegates to launch_process to start a new process. It requires the path, arguments, environment, and flags for the process.

```cpp
{
  return process_handle::launch_process(_path, _args, _env, _flags);
}
```

--------------------------------

### Get Handle Flags

Source: https://ned14.github.io/llfio/classllfio__v2__xxx_1_1pipe__handle.html

Retrieves the flags with which the handle was opened.

```APIDOC
## flags

### Description
The flags this handle was opened with.

### Method
flag flags () const noexcept
```

--------------------------------

### Process Handle Launching

Source: https://ned14.github.io/llfio/classllfio__v2__xxx_1_1process__handle.html

Functions for launching new processes.

```APIDOC
## ◆ launch_process() [1/2]

### Description
This is an overloaded member function, provided for convenience. It differs from the other `launch_process` function only in what argument(s) it accepts.

### Method
`static result< process_handle > llfio_v2_xxx::process_handle::launch_process(path_view path, span< path_view_component > args, flag flags = flag::wait_on_close) noexcept`
```

```APIDOC
## ◆ launch_process() [2/2]

### Description
Creates a new process launching the binary at the specified `path`. This is the only handle creation function in LLFIO which requires an absolute path due to platform limitations in non-intrusively emulating race-free process launch.

### Method
`static result< process_handle > llfio_v2_xxx::process_handle::launch_process(path_view path, span< path_view_component > args, span< path_view_component > env = *current().environment(), flag flags = flag::wait_on_close) noexcept`

### Parameters
#### Path Parameter
- **path** (path_view) - The absolute path to the binary to launch.

#### Arguments
- **args** (span< path_view_component >) - An array of arguments to pass to the process.
- **env** (span< path_view_component >) - An array of environment variables to set for the process, defaults to the current process' environment.
- **flags** (flag) - Any additional custom behaviors, defaults to `flag::wait_on_close`.

### Errors
Returns any of the values POSIX `posix_spawn()` or `CreateProcess()` can return.
```

--------------------------------

### open

Source: https://ned14.github.io/llfio/classkvstore__v1__xxx_1_1basic__key__value__store-members.html

Opens a key-value store entry. Supports read mode by default.

```APIDOC
## open

### Description
Opens a key-value store entry.

### Method
virtual int open(key_type key, mode _mode = mode::read) noexcept = 0

### Parameters
#### Path Parameters
- **key** (key_type) - Description of the key to open.
- **_mode** (mode) - Optional. The mode to open the store in, defaults to mode::read.

### Response
#### Success Response (0)
Indicates successful opening of the store entry.

#### Error Response
Non-zero value indicates an error.
```

--------------------------------

### parent_path_handle

Source: https://ned14.github.io/llfio/functions_func_p.html

Gets the file system handle for the parent path.

```APIDOC
## parent_path_handle()

### Description
Returns a file system handle to the parent directory.

### Method
N/A (Function Signature)

### Endpoint
N/A

### Parameters
None

### Request Example
None

### Response
#### Success Response
- **return value** (llfio_v2_xxx::fs_handle) - An fs_handle to the parent path.
```

--------------------------------

### Directory Creation and Access

Source: https://ned14.github.io/llfio/classllfio__v2__xxx_1_1directory__handle.html

Static methods for creating and accessing directories.

```APIDOC
## Static Public Member Functions

### `directory(const path_handle &base, path_view_type path, mode _mode=mode::read, creation _creation=creation::open_existing, caching _caching=caching::all, flag flags=flag::none) noexcept`
Creates or opens a directory handle.

### `uniquely_named_directory(const path_handle &dirpath, mode _mode=mode::write, caching _caching=caching::temporary, flag flags=flag::none) noexcept`
Creates a uniquely named directory.

### `temp_directory(path_view_type name=path_view_type(), mode _mode=mode::write, creation _creation=creation::if_needed, caching _caching=caching::all, flag flags=flag::none) noexcept`
Creates a temporary directory.

### `exists(const path_handle &base, path_view_type path) noexcept`
Checks if a path exists.

### `path(const path_handle &base, path_view_type path) noexcept`
Gets the path handle for a given path.

### `path(path_view_type _path) noexcept`
Gets the path handle for a given path view.
```

--------------------------------

### llfio_v2_xxx::maximum_extent

Source: https://ned14.github.io/llfio/file__handle_8hpp.html

Gets the maximum extent (size) of a file.

```APIDOC
## llfio_v2_xxx::maximum_extent

### Description
Gets the maximum extent (size) of a file.

### Signature
`result<file_handle::extent_type> maximum_extent(const file_handle &self) noexcept`
```

--------------------------------

### try_parent_path_handle

Source: https://ned14.github.io/llfio/classllfio__v2__xxx_1_1fast__random__file__handle-members.html

Attempts to non-blockingly get a handle to the parent directory.

```APIDOC
## try_parent_path_handle

### Description
Attempts to non-blockingly get a handle to the parent directory of the current file handle. This operation is part of the `fs_handle` interface.

### Method
`try_parent_path_handle`

### Parameters
This method accepts a variable number of arguments (`Args &&... args`).

### Returns
Returns a `llfio_v2_xxx::fs_handle` representing the parent directory if successful.
```

--------------------------------

### enumerate_kvstores

Source: https://ned14.github.io/llfio/namespacekvstore__v1__xxx.html

Fills an array with information about all available key-value stores for the current process.

```APIDOC
## enumerate_kvstores

### Description
Fill an array with information about all the key value stores available to this process.

### Method
result< span< basic_key_value_store_info > >

### Parameters
- **lst** (span< basic_key_value_store_info >) - Required - The span to fill with store information.

### Response
#### Success Response
- **span< basic_key_value_store_info >** - The span filled with information about available key-value stores.
```

--------------------------------

### path_view::begin()

Source: https://ned14.github.io/llfio/classllfio__v2__xxx_1_1path__view-members.html

Returns an iterator to the beginning of the path view.

```APIDOC
## begin()

### Description
Returns an iterator to the beginning of the path view.

### Method
inline

### Endpoint
N/A (Method)
```

--------------------------------

### deallocate

Source: https://ned14.github.io/llfio/classllfio__v2__xxx_1_1utils_1_1page__allocator-members.html

Deallocates storage for n elements starting at pointer p.

```APIDOC
## deallocate(pointer p, size_type n)

### Description
Deallocates storage for n elements starting at pointer p.

### Method
inline

### Parameters
- **p** (pointer) - Pointer to the memory to deallocate.
- **n** (size_type) - The number of elements to deallocate.
```

--------------------------------

### QUICKCPPLIB_BITFIELD_BEGIN_T()

Source: https://ned14.github.io/llfio/functions_func_q.html

This macro is used for defining bitfields. It is associated with directory_handle, handle, and native_handle_type.

```APIDOC
## QUICKCPPLIB_BITFIELD_BEGIN_T()

### Description
Defines the beginning of a bitfield. This macro is used in conjunction with other bitfield macros to define bitfields within classes.

### Associated Types
- llfio_v2_xxx::directory_handle
- llfio_v2_xxx::handle
- llfio_v2_xxx::native_handle_type
```

--------------------------------

### Get Native Handle

Source: https://ned14.github.io/llfio/classllfio__v2__xxx_1_1pipe__handle.html

Retrieves the native handle used by this handle.

```APIDOC
## native_handle

### Description
The native handle used by this handle.

### Method
native_handle_type native_handle () const noexcept
```

--------------------------------

### page_size()

Source: https://ned14.github.io/llfio/classllfio__v2__xxx_1_1map__handle.html

Gets the page size of the map in bytes. This is a const method.

```APIDOC
## page_size()

### Description
Returns the page size used by the map, in bytes.

### Method
const

### Returns
size_type: The page size in bytes.
```

--------------------------------

### Create Directory Handle (llfio_v2_xxx::directory)

Source: https://ned14.github.io/llfio/namespacellfio__v2__xxx.html

Creates a handle for accessing a directory at the specified path. Supports various options for mode, creation, caching, and flags. Errors are returnable from POSIX open() or CreateFile().

```cpp
return directory_handle::directory(std::forward<decltype(base)>(base), std::forward<decltype(path)>(path), std::forward<decltype(_mode)>(_mode),
std::forward<decltype(_creation)>(_creation), std::forward<decltype(_caching)>(_caching),
std::forward<decltype(flags)>(flags));
```

--------------------------------

### pre_enumeration

Source: https://ned14.github.io/llfio/structllfio__v2__xxx_1_1algorithm_1_1traverse__visitor-members.html

Called before the contents of a directory are enumerated. Allows for pre-processing or setup.

```APIDOC
## pre_enumeration

### Description
Called before the contents of a directory are enumerated. Allows for pre-processing or setup.

### Signature
`virtual void pre_enumeration(void *data, const directory_handle &dirh, size_t depth) noexcept`

### Parameters
- **data** (void *) - User-provided data.
- **dirh** (const directory_handle &) - The directory handle.
- **depth** (size_t) - The current depth of the traversal.
```

--------------------------------

### Default Constructor for llfio_v2_xxx::file_handle

Source: https://ned14.github.io/llfio/classllfio__v2__xxx_1_1file__handle.html

Provides a default constructor for llfio_v2_xxx::file_handle. This is a simple default initialization.

```cpp
constexpr llfio_v2_xxx::file_handle::file_handle() noexcept = default;
```

--------------------------------

### Functions starting with 'a'

Source: https://ned14.github.io/llfio/functions_func_a.html

This section details functions in LLFIO v2.00 that begin with the letter 'a'.

```APIDOC
## a

### address()

- **Description**: Returns the address of the mapped memory.
- **Returns**: `llfio_v2_xxx::map_handle`, `llfio_v2_xxx::mapped_file_handle`

### allocator()

- **Description**: Returns the allocator used by the path view component.
- **Returns**: `kvstore_v1_xxx::basic_key_value_store`, `llfio_v2_xxx::path_view_component::rendered_path< ZeroTermination, T, AllocatorOrDeleter, _internal_buffer_size, type >`

### anonymous_pipe()

- **Description**: Creates an anonymous pipe.
- **Returns**: `llfio_v2_xxx::pipe_handle`

### are_reads_from_cache()

- **Description**: Checks if reads are served from cache.
- **Returns**: `bool` (from `llfio_v2_xxx::handle`)

### are_safety_barriers_issued()

- **Description**: Checks if safety barriers have been issued.
- **Returns**: `bool` (from `llfio_v2_xxx::handle`)

### are_writes_durable()

- **Description**: Checks if writes are durable.
- **Returns**: `bool` (from `llfio_v2_xxx::handle`)

### as_span()

- **Description**: Converts the mapped object to a span.
- **Returns**: `llfio_v2_xxx::map_handle`, `llfio_v2_xxx::mapped< T >`

### assign()

- **Description**: Assigns a new value to the vector.
- **Returns**: `void` (from `llfio_v2_xxx::algorithm::impl::trivial_vector_impl< has_default_construction, T >`)

### at()

- **Description**: Accesses an element at a specific index.
- **Returns**: `T&` (from `llfio_v2_xxx::algorithm::impl::trivial_vector_impl< has_default_construction, T >`)

### atomic_append()

- **Description**: Atomically appends data to a file.
- **Returns**: `void` (from `llfio_v2_xxx::algorithm::shared_fs_mutex`)
```

--------------------------------

### Create Path Handle (with base)

Source: https://ned14.github.io/llfio/namespacellfio__v2__xxx.html

Creates a path handle for accessing a file system location. Uses an efficient OS-specific method if available, otherwise opens a directory with read-only permissions. Errors can be any POSIX open() or CreateFile() error.

```cpp
| result< path_handle > llfio_v2_xxx::path  | ( | const path_handle & | _base_ ,
| path_handle::path_view_type | _path_
)
inlinenoexcept
172{
173 return path_handle::path(std::forward<decltype(base)>(base), std::forward<decltype(path)>(path));
174}
```

--------------------------------

### try_parent_path_handle_until

Source: https://ned14.github.io/llfio/classllfio__v2__xxx_1_1fs__handle-members.html

Attempts to get the parent path handle until a specified time point.

```APIDOC
## try_parent_path_handle_until

### Description
Attempts to get the parent path handle until a specified time point.

### Method
inline

### Parameters
- **Args &&... args** - Forwarded arguments for getting the parent path handle.
- **timeout** (const std::chrono::time_point< Clock, Duration > &) - The time point until which the operation can proceed.

### Endpoint
N/A (This is a class method, not an HTTP endpoint)

### Request Example
N/A

### Response
N/A
```

--------------------------------

### try_parent_path_handle_for

Source: https://ned14.github.io/llfio/classllfio__v2__xxx_1_1fs__handle-members.html

Attempts to get the parent path handle within a specified duration.

```APIDOC
## try_parent_path_handle_for

### Description
Attempts to get the parent path handle within a specified duration.

### Method
inline

### Parameters
- **Args &&... args** - Forwarded arguments for getting the parent path handle.
- **duration** (const std::chrono::duration< Rep, Period > &) - The duration within which the operation must complete.

### Endpoint
N/A (This is a class method, not an HTTP endpoint)

### Request Example
N/A

### Response
N/A
```

--------------------------------

### mapped_file_handle::mapped_file_handle (conversion from file_handle with mapping)

Source: https://ned14.github.io/llfio/classllfio__v2__xxx_1_1mapped__file__handle.html

This constructor allows for explicit conversion from a file_handle and attempts to map the file. It takes a file_handle, reservation size, section flags, and an offset. It initializes the base file_handle, offset, and section handle, and then attempts to reserve and map the file.

```APIDOC
## mapped_file_handle() [conversion from file_handle with mapping]

### Description
Explicit conversion from file_handle permitted, this overload also attempts to map the file.

### Method Signature
`template<class SHF>
mapped_file_handle::mapped_file_handle(file_handle &&o, size_type _reservation_, SHF _sflags_, extent_type _offset_)`

### Parameters
- `o` (file_handle &&): The file handle to move from.
- `_reservation_` (size_type): The reservation size for mapping.
- `_sflags_` (SHF): Section flags.
- `_offset_` (extent_type): The offset within the file.

### Notes
- Attempts to reserve and map the file. If mapping fails and the file length is not zero, an exception is thrown. If the file length is zero, the error is sunk.
- Performs assertions to check consistency of native handles if the mapped handle is valid.
```
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