### Run MySQL Docker Container and Setup Database

Source: https://www.boost.org/doc/libs/latest/libs/mysql/doc/html/mysql/examples.html

This snippet shows how to run a MySQL Docker container and load the necessary example database. It includes commands for starting the container and importing the SQL setup script.

```bash
# Remove the "-v /var/run/mysqld:/var/run/mysqld" part if you don't need UNIX sockets
> docker run --name some-mysql -p 3306:3306 -v /var/run/mysqld:/var/run/mysqld -d -e MYSQL_ROOT_PASSWORD= -e MYSQL_ALLOW_EMPTY_PASSWORD=1 -d mysql

# All the required data can be loaded by running example/db_setup.sql.
# If you're using the above container, the root user has a blank password
> mysql -u root < example/db_setup.sql

```

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

### Main Function Setup

Source: https://www.boost.org/doc/libs/latest/libs/beast/example/http/server/async/http_server_async.cpp

Parses command-line arguments, initializes the io_context, and starts the listener.

```cpp
int main(int argc, char* argv[])
{
    // Check command line arguments.
    if (argc != 5)
    {
        std::cerr <<
            "Usage: http-server-async <address> <port> <doc_root> <threads>\n" <<
            "Example:\n" <<
            "    http-server-async 0.0.0.0 8080 . 1\n";
        return EXIT_FAILURE;
    }
    auto const address = net::ip::make_address(argv[1]);
    auto const port = static_cast<unsigned short>(std::atoi(argv[2]));
    auto const doc_root = std::make_shared<std::string>(argv[3]);
    auto const threads = std::max<int>(1, std::atoi(argv[4]));

    // The io_context is required for all I/O
    net::io_context ioc{threads};

    // Create and launch a listening port
    std::make_shared<listener>(
        ioc,
        tcp::endpoint{address, port},
        doc_root)->run();

    // Run the I/O service on the requested number of threads
    std::vector<std::thread> v;
    v.reserve(threads - 1);
    for(auto i = threads - 1; i > 0; --i)
        v.emplace_back(
        [&ioc]
        {
            ioc.run();
        });
    ioc.run();

    return EXIT_SUCCESS;
}
```

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

### Main Function for Mutual Exclusion Example

Source: https://www.boost.org/doc/libs/latest/doc/html/boost_asio/example/cpp20/channels/mutual_exclusion_1.cpp

Sets up the Boost.Asio io_context, resolves the listen endpoint, and starts the acceptor. It also spawns the listener coroutine and runs the io_context. Handles potential exceptions during setup.

```cpp
int main(int argc, char* argv[])
{
  try
  {
    if (argc != 3)
    {
      std::cerr << "Usage: mutual_exclusion_1";
      std::cerr << " <listen_address> <listen_port>\n";
      return 1;
    }

    io_context ctx;

    auto listen_endpoint =
      *tcp::resolver(ctx).resolve(argv[1], argv[2],
          tcp::resolver::passive).begin();

    tcp::acceptor acceptor(ctx, listen_endpoint);
    co_spawn(ctx, listen(acceptor), detached);
    ctx.run();
  }
  catch (std::exception& e)
  {
    std::cerr << "Exception: " << e.what() << "\n";
  }
}
```

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

### Example Directory Change

Source: https://www.boost.org/doc/libs/latest/more/getting_started/windows.html

An example of changing the current directory to a Boost installation path. Adjust the path according to your Boost installation.

```bash
cd `C:\Program Files\boost\``boost_1_82_0`
```

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

### Boost.Asio Async Accept Example

Source: https://www.boost.org/doc/libs/latest/doc/html/boost_asio/reference/basic_socket_acceptor/async_accept/overload1.html

An example demonstrating how to use `async_accept` to initiate an asynchronous connection acceptance. It includes a completion handler and the acceptor setup.

```cpp
void accept_handler(const boost::system::error_code& error)
{
  if (!error)
  {
    // Accept succeeded.
  }
}

... 

boost::asio::ip::tcp::acceptor acceptor(my_context);
... 
boost::asio::ip::tcp::socket socket(my_context);
acceptor.async_accept(socket, accept_handler);


```

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

### SSL Server Setup

Source: https://www.boost.org/doc/libs/latest/doc/html/boost_asio/example/cpp11/ssl/server.cpp

Initializes the Boost.Asio SSL server, configures the SSL context, and starts accepting connections.

```cpp
#include <cstdlib>
#include <functional>
#include <iostream>
#include <boost/asio.hpp>
#include <boost/asio/ssl.hpp>

using boost::asio::ip::tcp;

class server
{
public:
  server(boost::asio::io_context& io_context, unsigned short port)
    : acceptor_(io_context, tcp::endpoint(tcp::v4(), port)),
      context_(boost::asio::ssl::context::sslv23)
  {
    context_.set_options(
        boost::asio::ssl::context::default_workarounds
        | boost::asio::ssl::context::no_sslv2
        | boost::asio::ssl::context::single_dh_use);
    context_.set_password_callback(std::bind(&server::get_password, this));
    context_.use_certificate_chain_file("server.pem");
    context_.use_private_key_file("server.pem", boost::asio::ssl::context::pem);
    context_.use_tmp_dh_file("dh4096.pem");

    do_accept();
  }

private:
  std::string get_password() const
  {
    return "test";
  }

  void do_accept()
  {
    acceptor_.async_accept(
        [this](const boost::system::error_code& error, tcp::socket socket)
        {
          if (!error)
          {
            std::make_shared<session>(
                boost::asio::ssl::stream<tcp::socket>(
                  std::move(socket), context_))->start();
          }

          do_accept();
        });
  }

  tcp::acceptor acceptor_;
  boost::asio::ssl::context context_;
};
```

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

### Configuration File Example

Source: https://www.boost.org/doc/libs/latest/libs/wave/doc/wave_driver.html

This snippet shows an example of a Wave configuration file, demonstrating how to enable features like variadics, timer support, emulate specific GCC versions, and add include search paths.

```bash
# 
# enable variadics et.al. in C++ mode
#
--variadics
#
# enable timer support
#
--timer
#
# emulate gcc V3.3.2
#
-D__GNUC__=3
-D__GNUC_MINOR__=3
-D__GNUC_PATCHLEVEL__=2
-D__GNUG__
# 
# add Boost to the system include search paths
#
-S/usr/local/boost
```

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

### Main Program Setup for MySQL Connection Pool

Source: https://www.boost.org/doc/libs/latest/libs/mysql/doc/html/mysql/tutorial_connection_pool.html

Initializes the io_context, configures MySQL connection pool parameters, and starts the pool. This snippet is the core setup for the server application.

```cpp
// Create an I/O context, required by all I/O objects
asio::io_context ctx;

// pool_params contains configuration for the pool.
// You must specify enough information to establish a connection,
// including the server address and credentials.
// You can configure a lot of other things, like pool limits
mysql::pool_params params;
params.server_address.emplace_host_and_port(server_hostname);
params.username = username;
params.password = password;
params.database = "boost_mysql_examples";

// Construct the pool.
// ctx will be used to create the connections and other I/O objects
mysql::connection_pool pool(ctx, std::move(params));

// You need to call async_run on the pool before doing anything useful with it.
// async_run creates connections and keeps them healthy. It must be called
// only once per pool.
// The detached completion token means that we don't want to be notified when
// the operation ends. It's similar to a no-op callback.
pool.async_run(asio::detached);

```

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

### Running the Example Program

Source: https://www.boost.org/doc/libs/latest/more/getting_started/windows.html

Command to run the compiled Boost example program, redirecting input from 'jayne.txt'.

```bash
_path_/_to_/example < _path_/_to_/jayne.txt

```

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

### Install Boost.Build

Source: https://www.boost.org/doc/libs/latest/more/getting_started/windows.html

Steps to build and install Boost.Build from its source directory.

```bash
b2 install --prefix=_PREFIX_
```

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

### Main Function Setup

Source: https://www.boost.org/doc/libs/latest/libs/beast/example/http/server/sync-ssl/http_server_sync_ssl.cpp

Initializes the server, parses command-line arguments for address, port, and document root, and sets up the io_context and SSL context. Includes basic argument validation.

```cpp
int main(int argc, char* argv[])
{
    try
    {
        // Check command line arguments.
        if (argc != 4)
        {
            std::cerr <<
                "Usage: http-server-sync-ssl <address> <port> <doc_root>\n" <<
                "Example:\n" <<
                "    http-server-sync-ssl 0.0.0.0 8080 .\n";
            return EXIT_FAILURE;
        }
        auto const address = net::ip::make_address(argv[1]);
        auto const port = static_cast<unsigned short>(std::atoi(argv[2]));
        auto const doc_root = std::make_shared<std::string>(argv[3]);

        // The io_context is required for all I/O
        net::io_context ioc{1};

        // The SSL context is required, and holds certificates
        ssl::context ctx{ssl::context::tlsv12};


```

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

### Recommended Setup for Database Selection

Source: https://www.boost.org/doc/libs/latest/libs/redis/doc/html/redis/reference/boost/redis/config/database_index.html

This snippet demonstrates the recommended approach to select a database index using the `setup` field. Set `use_setup` to true and push a 'SELECT' command with the desired database index.

```cpp
cfg.use_setup = true;
cfg.setup.push("SELECT", 4); // select database index 4
```

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

### HTTP GET Request Example

Source: https://www.boost.org/doc/libs/latest/doc/antora/url/urls/components.html

An example of a complete HTTP/1.1 GET request. The URL's scheme is implied by the context of the request.

```http
GET /index.htm HTTP/1.1
Host: www.example.com
Accept: text/html
User-Agent: Beast
```

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

### Install Boost.Build

Source: https://www.boost.org/doc/libs/latest/more/getting_started/unix-variants.html

Steps to build and install Boost.Build from source. Ensure the installation prefix and its bin directory are added to your PATH.

```bash
cd tools/build/
bash bootstrap.sh
b2 install --prefix=_PREFIX_
export PATH=_PREFIX_/bin:$PATH
```

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

### Main Server Entry Point

Source: https://www.boost.org/doc/libs/latest/doc/html/boost_asio/example/cpp11/ssl/server.cpp

Sets up the Boost.Asio io_context and starts the SSL server, handling command-line arguments for the port.

```cpp
int main(int argc, char* argv[])
{
  try
  {
    if (argc != 2)
    {
      std::cerr << "Usage: server <port>\n";
      return 1;
    }

    boost::asio::io_context io_context;

    using namespace std;
    server s(io_context, atoi(argv[1]));

    io_context.run();
  }
  catch (std::exception& e)
  {
    std::cerr << "Exception: " << e.what() << "\n";
  }

  return 0;
}
```

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

### Compile and Run Boost.Filesystem Tutorial Example (Windows)

Source: https://www.boost.org/doc/libs/latest/libs/filesystem/doc/tutorial.html

Commands to navigate to the example directory, compile the tutorial programs using b2, and run the tut1 example on Microsoft Windows.

```batch
>cd _**boost-root**_\libs\filesystem\example

>b2.exe tutorial
Compiling example programs...

>tut1
Usage: tut1 path
```

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

### start

Source: https://www.boost.org/doc/libs/latest/boost/container/vector.hpp

Gets or sets the starting pointer of the allocated memory.

```APIDOC
## start

### Description
Gets or sets the starting pointer of the allocated memory.

### Method
`pointer` (getter) or `void` (setter)

### Parameters
- **p** (const pointer &) - The pointer to set (for the setter).
```

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

### Compile and Run Boost.Filesystem Tutorial Example (Linux)

Source: https://www.boost.org/doc/libs/latest/libs/filesystem/doc/tutorial.html

Commands to navigate to the example directory, compile the tutorial programs using b2, and run the tut1 example on Ubuntu Linux.

```bash
$ cd _**boost-root**_/libs/filesystem/example

$ b2 tutorial
Compiling example programs...

$ ./tut1
Usage: tut1 path
```

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

### DST Start Date Rule Examples

Source: https://www.boost.org/doc/libs/latest/boost/date_time/tz_db_base.hpp

Provides examples of the specially formatted strings used to define the start date rule for daylight saving time transitions.

```cpp
"-1;5;9"="Last Friday of September", 
"2;1;3"="Second Monday of March"
```

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

### Get the beginning of a local_time_period

Source: https://www.boost.org/doc/libs/latest/doc/html/date_time/local_time.html

Retrieves the starting local_date_time of the period. This is the inclusive start of the range.

```cpp
time_zone_ptr 
  zone(new posix_time_zone("MST-07"));
local_date_time 
  ldt((ptime(date(2005,Jan,1)),hours(0)), zone);
local_time_period ltp(ldt, hours(2));
ltp.begin(); // => 2005-Jan-01 00:00:00
```

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

### Main Function Example Setup

Source: https://www.boost.org/doc/libs/latest/libs/fiber/examples/adapt_method_calls.cpp

Initializes the `AsyncAPI` with sample data in the `main` function to prepare for demonstrating asynchronous operations.

```cpp
/*****************************************************************************
*   driving logic
*****************************************************************************/
int main(int argc, char *argv[]) {
    // prime AsyncAPI with some data
    AsyncAPI api("abcd");

```

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

### Main Function Setup

Source: https://www.boost.org/doc/libs/latest/doc/html/boost_asio/tutorial/tutdaytime4.html

Sets up the main function, including argument checking and initializing the io_context.

```cpp
int main(int argc, char* argv[])
{
  try
  {
    if (argc != 2)
    {
      std::cerr << "Usage: client <host>" << std::endl;
      return 1;
    }

    boost::asio::io_context io_context;

```

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

### foldl_reject_incomplete Example Setup

Source: https://www.boost.org/doc/libs/latest/doc/html/metaparse/reference.html

Defines helper parsers and metafunctions used in examples for foldl_reject_incomplete.

```cpp
using int_token = token<int_>;
using plus_token = token<lit_c<'+'>>;
using plus_int = last_of<plus_token, int_token>;
using sum_op = mpl::lambda<mpl::plus<mpl::_1, mpl::_2>>::type;

```

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

### Get Period Start Character

Source: https://www.boost.org/doc/libs/latest/doc/html/doxygen/date_time_reference/classboost_1_1date__time_1_1iso__format__base_3_01wchar__t_01_4.html

Returns the ISO 8601 character indicating the start of a period.

```cpp
static wchar_t period_start_char();
```

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

### Main Function and Setup

Source: https://www.boost.org/doc/libs/latest/doc/html/boost_asio/example/cpp20/channels/throttling_proxy.cpp

Parses command-line arguments for listen and target endpoints, sets up the io_context, resolver, and acceptor, and starts the listening coroutine. Includes basic error handling for incorrect usage and exceptions.

```cpp
int main(int argc, char* argv[])
{
  try
  {
    if (argc != 5)
    {
      std::cerr << "Usage: throttling_proxy";
      std::cerr << " <listen_address> <listen_port>";
      std::cerr << " <target_address> <target_port>\n";
      return 1;
    }

    io_context ctx;

    auto listen_endpoint =
      *tcp::resolver(ctx).resolve(argv[1], argv[2],
          tcp::resolver::passive).begin();

    auto target_endpoint =
      *tcp::resolver(ctx).resolve(argv[3], argv[4]).begin();

    tcp::acceptor acceptor(ctx, listen_endpoint);
    co_spawn(ctx, listen(acceptor, target_endpoint), detached);
    ctx.run();
  }
  catch (std::exception& e)
  {
    std::cerr << "Exception: " << e.what() << "\n";
  }
}

```

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

### Get Local DST Start Day

Source: https://www.boost.org/doc/libs/latest/boost/date_time/dst_rules.hpp

Retrieves the date of the DST start for a given year.

```C++
static date_type local_dst_start_day(year_type year)
{
  return dst_traits::local_dst_start_day(year);
}
```

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

### Main Function: HTTP Server Setup and Run

Source: https://www.boost.org/doc/libs/latest/libs/beast/example/http/server/async-local/http_server_async_local.cpp

Entry point for the HTTP server. Parses command-line arguments, sets up the io_context, creates a listener, and starts the server threads.

```C++
int main(int argc, char* argv[])
{
    try
    {
        // Check command line arguments.
        if (argc != 4)
        {
            std::cerr <<
                "Usage: http-server-async-local <path> <doc_root> <threads>\n" <<
                "Example:\n" <<
                "    http-server-async-local /tmp/http.sock . 1\n";
            return EXIT_FAILURE;
        }
        auto const path = argv[1];
        auto const doc_root = std::make_shared<std::string>(argv[2]);
        auto const threads = std::max<int>(1, std::atoi(argv[3]));

        // The io_context is required for all I/O
        net::io_context ioc{threads};

        // Remove previous binding
        std::remove(path);

        // Create and launch a listening port
        std::make_shared<listener>(
            ioc,
            stream_protocol::endpoint{path},
            doc_root)->run();

        // Run the I/O service on the requested number of threads
        std::vector<std::thread> v;
        v.reserve(threads - 1);
        for(auto i = threads - 1; i > 0; --i)
            v.emplace_back(
            [&ioc]
            {
                ioc.run();
            });
        ioc.run();

        return EXIT_SUCCESS;
    }
    catch(std::exception const& e)
    {
        std::cerr << e.what() << std::endl;
        return EXIT_FAILURE;
    }
}
```

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

### Main Function and IO Context Setup

Source: https://www.boost.org/doc/libs/latest/libs/beast/example/websocket/server/awaitable/websocket_server_awaitable.cpp

Sets up the Boost.Asio IO context, parses command-line arguments for address, port, and thread count, and starts the server. It also manages a pool of threads to run the IO context.

```cpp
int
main(int argc, char* argv[])
{
    // Check command line arguments.
    if(argc != 4)
    {
        std::cerr
            << "Usage: websocket-server-awaitable <address> <port> <threads>\n"
            << "Example:\n"
            << "    websocket-server-awaitable 0.0.0.0 8080 1\n";
        return EXIT_FAILURE;
    }
    auto const address = net::ip::make_address(argv[1]);
    auto const port    = static_cast<unsigned short>(std::atoi(argv[2]));
    auto const threads = std::max<int>(1, std::atoi(argv[3]));

    // The io_context is required for all I/O
    net::io_context ioc(threads);

    // Spawn a listening port
    net::co_spawn(
        ioc,
        do_listen(net::ip::tcp::endpoint{ address, port }),
        [](std::exception_ptr e)
        {
            if(e)
            {
                try
                {
                    std::rethrow_exception(e);
                }
                catch(std::exception const& e)
                {
                    std::cerr << "Error: " << e.what() << std::endl;
                }
            }
        });

    // Run the I/O service on the requested number of threads
    std::vector<std::thread> v;
    v.reserve(threads - 1);
    for(auto i = threads - 1; i > 0; --i)
        v.emplace_back([&ioc] { ioc.run(); });
    ioc.run();

    return EXIT_SUCCESS;
}

#else

int
main(int, char*[])
{
    std::printf("awaitables require C++20\n");
    return EXIT_FAILURE;
}

#endif

```

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

### Get Start Index of index_range

Source: https://www.boost.org/doc/libs/latest/doc/html/MultiArray.html

Retrieve the start index of an index_range object. If the start index is not specified, it returns the provided default value idx.

```cpp
i.start()
```

```cpp
i.get_start(idx)
```

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

### Main Function and Server Initialization

Source: https://www.boost.org/doc/libs/latest/doc/html/boost_asio/example/cpp11/handler_tracking/async_tcp_echo_server.cpp

Sets up the Boost.Asio io_context, initializes the server with a specified port, and runs the event loop.

```cpp
int main(int argc, char* argv[])
{
  try
  {
    if (argc != 2)
    {
      std::cerr << "Usage: async_tcp_echo_server <port>\n";
      return 1;
    }

    boost::asio::io_context io_context;

    server s(io_context, std::atoi(argv[1]));

    io_context.run();
  }
  catch (std::exception& e)
  {
    std::cerr << "Exception: " << e.what() << "\n";
  }

  return 0;
}
```

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

### DST Start Date Rule Examples

Source: https://www.boost.org/doc/libs/latest/doc/html/doxygen/date_time_reference/classboost_1_1date__time_1_1tz__db__base.html

Provides examples of the specially formatted strings used to define Daylight Saving Time start dates. These rules specify the 'nth' weekday of a given month for the transition.

```text
"-1;5;9"="Last Friday of September"
"2;1;3"="Second Monday of March"
```

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

### Get DST start day

Source: https://www.boost.org/doc/libs/latest/doc/html/doxygen/date_time_reference/structboost_1_1date__time_1_1acst__dst__trait.html

Retrieves the day of the week for the start of Daylight Saving Time for a given year.

```cpp
static day_of_week_type start_day(year_type);
```

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

### Install Boost Binaries

Source: https://www.boost.org/doc/libs/latest/more/getting_started/unix-variants.html

Build and install the Boost libraries to the configured installation prefix. The binaries will be located in the `lib/` subdirectory.

```bash
$ ./b2 install
```

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

### Hello, World! Example with Boost.Xpressive

Source: https://www.boost.org/doc/libs/latest/doc/html/xpressive/user_s_guide.html

Demonstrates basic usage of Boost.Xpressive for string matching and capturing groups. Requires including <boost/xpressive/xpressive.hpp> and using the boost::xpressive namespace.

```cpp
#include <iostream>
#include <boost/xpressive/xpressive.hpp>

using namespace boost::xpressive;

int main()
{
    std::string hello( "hello world!" );

    sregex rex = sregex::compile( "(\w+) (\w+)!" );
    smatch what;

    if( regex_match( hello, what, rex ) )
    {
        std::cout << what[0] << '\n'; // whole match
        std::cout << what[1] << '\n'; // first capture
        std::cout << what[2] << '\n'; // second capture
    }

    return 0;
}

```

```text
hello world!
hello
world

```

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

### Get Week Start Character

Source: https://www.boost.org/doc/libs/latest/doc/html/doxygen/date_time_reference/classboost_1_1date__time_1_1iso__format__base_3_01wchar__t_01_4.html

Returns the character used in mixed strings to identify the start of a week number.

```cpp
static wchar_t week_start_char();
```

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

### Lazy Generator Example Setup

Source: https://www.boost.org/doc/libs/latest/libs/spirit/doc/html/spirit/karma/reference/auxiliary/lazy.html

Includes and using declarations required for Boost.Spirit Karma lazy generator examples.

```c++
#include <boost/spirit/include/karma.hpp>
#include <boost/spirit/include/support_utree.hpp>
#include <boost/phoenix/core.hpp>
#include <boost/phoenix/operator.hpp>
#include <boost/fusion/include/std_pair.hpp>
#include <boost/proto/deep_copy.hpp>
#include <iostream>
#include <string>

namespace karma = boost::spirit::karma;
using boost::spirit::karma::_1;
using boost::spirit::ascii::string;
using boost::phoenix::val;

```

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

### Main Function for Server Setup

Source: https://www.boost.org/doc/libs/latest/libs/beast/example/websocket/server/stackless-ssl/websocket_server_stackless_ssl.cpp

The main function initializes the server, sets up the IO context, SSL context, and loads the server certificate. It then creates a listener to accept connections and starts the IO context on multiple threads.

```cpp
int main(int argc, char* argv[])
{
    // Check command line arguments.
    if (argc != 4)
    {
        std::cerr <<
            "Usage: websocket-server-async-ssl <address> <port> <threads>\n" <<
            "Example:\n" <<
            "    websocket-server-async-ssl 0.0.0.0 8080 1\n";
        return EXIT_FAILURE;
    }
    auto const address = net::ip::make_address(argv[1]);
    auto const port = static_cast<unsigned short>(std::atoi(argv[2]));
    auto const threads = std::max<int>(1, std::atoi(argv[3]));

    // The io_context is required for all I/O
    net::io_context ioc{threads};

    // The SSL context is required, and holds certificates
    ssl::context ctx{ssl::context::tlsv12};

    // This holds the self-signed certificate used by the server
    load_server_certificate(ctx);

    // Create and launch a listening port
    std::make_shared<listener>(ioc, ctx, tcp::endpoint{address, port})->run();

    // Run the I/O service on the requested number of threads
    std::vector<std::thread> v;
    v.reserve(threads - 1);
    for(auto i = threads - 1; i > 0; --i)
        v.emplace_back(
        [&ioc]
        {
            ioc.run();
        });
    ioc.run();

    return EXIT_SUCCESS;
}
```

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

### Get Time Start Character

Source: https://www.boost.org/doc/libs/latest/doc/html/doxygen/date_time_reference/classboost_1_1date__time_1_1iso__format__base_3_01wchar__t_01_4.html

Returns the character used to denote the start of the time portion in mixed date-time strings.

```cpp
static wchar_t time_start_char();
```

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

### Example Jayne.txt Content

Source: https://www.boost.org/doc/libs/latest/more/getting_started/windows.html

This is the content for the 'jayne.txt' file used in the example.

```text
To: George Shmidlap
From: Rita Marlowe
Subject: Will Success Spoil Rock Hunter?
---
See subject.


```

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

### Main Function for Server Setup and Execution

Source: https://www.boost.org/doc/libs/latest/libs/beast/example/http/server/stackless-ssl/http_server_stackless_ssl.cpp

Sets up the Boost.Asio I/O context, SSL context, and listener. Parses command-line arguments for address, port, document root, and thread count. Launches the server and manages worker threads.

```cpp
int main(int argc, char* argv[])
{
    // Check command line arguments.
    if (argc != 5)
    {
        std::cerr <<
            "Usage: http-server-stackless-ssl <address> <port> <doc_root> <threads>\n" <<
            "Example:\n" <<
            "    http-server-stackless-ssl 0.0.0.0 8080 . 1\n";
        return EXIT_FAILURE;
    }
    auto const address = net::ip::make_address(argv[1]);
    auto const port = static_cast<unsigned short>(std::atoi(argv[2]));
    auto const doc_root = std::make_shared<std::string>(argv[3]);
    auto const threads = std::max<int>(1, std::atoi(argv[4]));

    // The io_context is required for all I/O
    net::io_context ioc{threads};

    // The SSL context is required, and holds certificates
    ssl::context ctx{ssl::context::tlsv12};

    // This holds the self-signed certificate used by the server
    load_server_certificate(ctx);

    // Create and launch a listening port
    std::make_shared<listener>(
        ioc,
        ctx,
        tcp::endpoint{address, port},
        doc_root)->run();

    // Run the I/O service on the requested number of threads
    std::vector<std::thread> v;
    v.reserve(threads - 1);
    for(auto i = threads - 1; i > 0; --i)
        v.emplace_back(
        [&ioc]
        {
            ioc.run();
        });
    ioc.run();

    return EXIT_SUCCESS;
}
```

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

### Getting the remote endpoint with error handling

Source: https://www.boost.org/doc/libs/latest/doc/html/boost_asio/reference/basic_stream_socket/remote_endpoint/overload2.html

Example demonstrating how to get the remote endpoint of a TCP socket and check for errors.

```cpp
boost::asio::ip::tcp::socket socket(my_context);
...
bboost::system::error_code ec;
boost::asio::ip::tcp::endpoint endpoint = socket.remote_endpoint(ec);
if (ec)
{
  // An error occurred.
}

```

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

### Example Placeholder Usage

Source: https://www.boost.org/doc/libs/latest/more/getting_started.html

This example demonstrates the use of italicized text in examples as a descriptive placeholder for user-provided information.

```bash
$ echo "My name is _your name_"

```

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

### File System Initialization and Command Table Setup

Source: https://www.boost.org/doc/libs/latest/libs/multi_index/example/composite_keys.cpp

Initializes the file system with sample data and populates the command table with available commands. This sets up the environment for the command-line interface simulation.

```C++
/* table of commands, a map from command names to class command pointers */

typedef std::map<std::string,command*> command_table;
static command_table cmt;

int main()
{
  /* fill the file system with some data */

  file_system::iterator it0,it1;
  
  fs.insert(file_entry("usr.cfg",240,false,0));
  fs.insert(file_entry("memo.txt",2430,false,0));
  it0=fs.insert(file_entry("dev",0,true,0)).first;
    fs.insert(file_entry("tty0",128,false,&*it0));
    fs.insert(file_entry("tty1",128,false,&*it0));
  it0=fs.insert(file_entry("usr",0,true,0)).first;
    it1=fs.insert(file_entry("bin",0,true,&*it0)).first;
      fs.insert(file_entry("bjam",172032,false,&*it1));
  it0=fs.insert(file_entry("home",0,true,0)).first;
    it1=fs.insert(file_entry("andy",0,true,&*it0)).first;
      fs.insert(file_entry("logo.jpg",5345,false,&*it1)).first;
      fs.insert(file_entry("foo.cpp",890,false,&*it1)).first;
      fs.insert(file_entry("foo.hpp",93,false,&*it1)).first;
      fs.insert(file_entry("foo.html",750,false,&*it1)).first;
      fs.insert(file_entry("a.obj",12302,false,&*it1)).first;
      fs.insert(file_entry(".bash_history",8780,false,&*it1)).first;
    it1=fs.insert(file_entry("rachel",0,true,&*it0)).first;
      fs.insert(file_entry("test.py",650,false,&*it1)).first;
      fs.insert(file_entry("todo.txt",241,false,&*it1)).first;
      fs.insert(file_entry(".bash_history",9510,false,&*it1)).first;

  /* fill the command table */

  cmt["cd"]   =&cd;
  cmt["ls"]   =&ls;
  cmt["mkdir"]=&mkdir;

  /* main looop */

  for(;;){
    /* print out the current directory and the prompt symbol */

    if(current_dir)std::cout<<current_dir->name;
    std::cout=">";

    /* get an input line from the user: if empty, exit the program */

    std::string com;
    std::getline(std::cin,com);
    command_tokenizer tok(com,boost::char_separator<char>(" \t\n"));
    if(tok.begin()==tok.end())break; /* null command, exit */

    /* select the corresponding command and execute it */

    command_table::iterator it=cmt.find(*tok.begin());
    if(it==cmt.end()){
      std::cout<<"invalid command"<<std::endl;
      continue;
    }

    it->second->execute(boost::next(tok.begin()),tok.end());
  }
  
  return 0;
}
```

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

### Results Report Start Notification

Source: https://www.boost.org/doc/libs/latest/libs/test/doc/html/doxygen/a01004.html

Called at the beginning of a results report. Implement to perform any setup required before reporting starts.

```cpp
virtual void results_report_start(std::ostream & ostr) = 0;
```

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

### iota Example

Source: https://www.boost.org/doc/libs/latest/boost/compute/algorithm/iota.hpp

This example demonstrates how to use the `iota` algorithm to fill a vector with sequential values starting from 0. The `iota` function is called with iterators defining the range and the starting value. The result is a vector containing 0, 1, 2, and so on.

```cpp
// Fill vector 'vec' with values 0, 1, 2, ...
boost::compute::iota(vec.begin(), vec.end(), (cl_int)0, queue);
```

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

### Example Session: With Options and Positional Arguments

Source: https://www.boost.org/doc/libs/latest/doc/html/program_options/tutorial.html

Illustrates a complex command line with various options, including short and long forms for include paths, and positional arguments for input files.

```bash
$ **bin/gcc/debug/options_description --optimization 4 -I foo -I another/path --include-path third/include/path a.cpp b.cpp**
Include paths are: foo another/path third/include/path
Input files are: a.cpp b.cpp
Optimization level is 4


```

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

### Example b2 Invocation on Windows

Source: https://www.boost.org/doc/libs/latest/more/getting_started/windows.html

An example of a command-line session to build Boost libraries on Windows, specifying build directory, build type, and toolset.

```bash
C:\WINDOWS> cd `C:\Program Files\boost\`boost_1_82_0`
`C:\Program Files\boost\`boost_1_82_0`> b2 **^**
More? **--build-dir=**"C:\Documents and Settings\dave\build-boost" **^**
More? **--build-type=complete** **msvc** stage
```

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

### date_time_duration::start

Source: https://www.boost.org/doc/libs/latest/libs/locale/doc/html/date__time_8hpp_source.html

Gets the starting point of the date_time_duration.

```APIDOC
## start

### Description
Gets the starting point of the date_time_duration.

### Signature
```cpp
const date_time & start() const
```

### Returns
A const reference to the starting `date_time` object.
```

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

### Client Main Function and Setup

Source: https://www.boost.org/doc/libs/latest/doc/html/boost_asio/example/cpp11/porthopper/client.cpp

Sets up the Boost.Asio io_context, resolves the server host and port, and establishes a TCP control connection. It also creates a UDP socket for receiving data.

```cpp
#include <boost/asio.hpp>
#include <algorithm>
#include <cstdlib>
#include <exception>
#include <iostream>
#include <memory>
#include <string>
#include <utility>
#include "protocol.hpp"

using boost::asio::ip::tcp;
using boost::asio::ip::udp;

int main(int argc, char* argv[])
{
  try
  {
    if (argc != 3)
    {
      std::cerr << "Usage: client <host> <port>\n";
      return 1;
    }
    using namespace std;
    std::string host_name = argv[1];
    std::string port = argv[2];

    boost::asio::io_context io_context;

    tcp::resolver resolver(io_context);
    tcp::endpoint remote_endpoint = *resolver.resolve(host_name, port).begin();

    tcp::socket control_socket(io_context);
    control_socket.connect(remote_endpoint);

    udp::socket data_socket(io_context, udp::endpoint(udp::v4(), 0));

    udp::endpoint data_endpoint = data_socket.local_endpoint();

    control_request start = control_request::start(data_endpoint.port());
    boost::asio::write(control_socket, start.to_buffers());

    unsigned long last_frame_number = 0;
    for (;;)
    {
      for (int i = 0; i < 50; ++i)
      {
        frame f;
        data_socket.receive(f.to_buffers(), 0);
        if (f.number() > last_frame_number)
        {
          last_frame_number = f.number();
          std::cout << "\n" << f.payload();
        }
      }

      std::cout << " Starting renegotiation";

      udp::socket new_data_socket(io_context, udp::endpoint(udp::v4(), 0));

      udp::endpoint new_data_endpoint = new_data_socket.local_endpoint();

      control_request change =
          control_request::change(data_endpoint.port(), new_data_endpoint.port());
      boost::system::error_code control_result;
      boost::asio::async_write(control_socket, change.to_buffers(),
          [&](boost::system::error_code ec, std::size_t /*length*/)
          {
            control_result = ec;
          });

      frame f1;
      boost::system::error_code new_data_socket_result;
      new_data_socket.async_receive(f1.to_buffers(),
          [&](boost::system::error_code ec, std::size_t /*length*/)
          {
            new_data_socket_result = ec;
            if (!ec)
            {
              data_socket.close();
            }
          });
    }
  }
  catch (std::exception& e)
  {
    std::cerr << "Exception: " << e.what() << "\n";
  }
}

```

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

### deque_tie Usage Example

Source: https://www.boost.org/doc/libs/latest/libs/fusion/doc/html/fusion/container/generation/metafunctions/deque_tie.html

An example demonstrating how to use result_of::deque_tie to get the type of a deque containing references to an int and a double.

```cpp
result_of::deque_tie<int, double>::type
```

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

### Boost.Asio connect example

Source: https://www.boost.org/doc/libs/latest/doc/html/boost_asio/reference/connect/overload4.html

Example demonstrating how to use Boost.Asio's 'connect' function to establish a socket connection to a sequence of endpoints and handle potential errors.

```cpp
tcp::resolver r(my_context);
tcp::resolver::query q("host", "service");
tcp::resolver::results_type e = r.resolve(q);
tcp::socket s(my_context);
boost::system::error_code ec;
boost::asio::connect(s, e.begin(), e.end(), ec);
if (ec)
{
  // An error occurred.
}
```

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

### Example Build Action Message

Source: https://www.boost.org/doc/libs/latest/more/getting_started/windows.html

This is an example of a build action message that may appear during the Boost build process.

```text
_toolset-name_.c++ _long_/_path_/_to_/_file_/_being_/_built_

```

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

### Get Device Info Example (Auto Type)

Source: https://www.boost.org/doc/libs/latest/libs/compute/doc/html/doxygen/header_reference/classboost_1_1compute_1_1device.html

Example of how to retrieve device information where the return type is automatically deduced by the template.

```cpp
device.get_info<CL_DEVICE_MAX_COMPUTE_UNITS>();
```

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

### Configure Client and Publish Message

Source: https://www.boost.org/doc/libs/latest/libs/mqtt5/doc/html/mqtt5/intro.html

Illustrates configuring an MQTT 5 client, connecting to a broker, and publishing a "Hello World!" message with QoS 0. Ensure you replace placeholders like '<your-mqtt-broker>', '<your-client-id>', '<client-username>', '<client-pwd>', and '<topic>' with your actual values.

```cpp
#include <boost/mqtt5/mqtt_client.hpp>
#include <boost/mqtt5/types.hpp>

#include <boost/asio/io_context.hpp>
#include <boost/asio/detached.hpp>
#include <boost/asio/ip/tcp.hpp>

#include <iostream>

int main() {
    boost::asio::io_context ioc;

    boost::mqtt5::mqtt_client<boost::asio::ip::tcp::socket> c(ioc);

    c.brokers("<your-mqtt-broker>", 1883)
        .credentials("<your-client-id>", "<client-username>", "<client-pwd>")
        .async_run(boost::asio::detached);

    c.async_publish<boost::mqtt5::qos_e::at_most_once>(
        "<topic>", "Hello world!",
        boost::mqtt5::retain_e::no, boost::mqtt5::publish_props {},
        [&c](boost::mqtt5::error_code ec) {
            std::cout << ec.message() << std::endl;
            c.async_disconnect(boost::asio::detached); // disconnect and close the Client
        }
    );

    ioc.run();
}

```

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

### Placeholder in Command Line Example

Source: https://www.boost.org/doc/libs/latest/more/getting_started/index.html

Illustrates the use of italicized text in command-line examples as a placeholder for user-provided information.

```bash
**$** echo "My name is _your name_"

```

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

### Build Action Message Example

Source: https://www.boost.org/doc/libs/latest/more/getting_started/unix-variants.html

An example of a build action message that might appear during the Boost build process.

```shell
_toolset-name_.c++ _long_/_path_/_to_/_file_/_being_/_built_
```

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

### Main Function and Client Initialization

Source: https://www.boost.org/doc/libs/latest/doc/html/boost_asio/example/cpp11/http/client/async_client.cpp

Sets up the Boost.Asio io_context and initializes the asynchronous HTTP client. Handles command-line arguments for server and path.

```cpp
int main(int argc, char* argv[])
{
  try
  {
    if (argc != 3)
    {
      std::cout << "Usage: async_client <server> <path>\n";
      std::cout << "Example:\n";
      std::cout << "  async_client www.boost.org /LICENSE_1_0.txt\n";
      return 1;
    }

    boost::asio::io_context io_context;
    client c(io_context, argv[1], argv[2]);
    io_context.run();
  }
  catch (std::exception& e)
  {
    std::cout << "Exception: " << e.what() << "\n";
  }

  return 0;
}
```

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

### Getting the local endpoint of a TCP acceptor

Source: https://www.boost.org/doc/libs/latest/doc/html/boost_asio/reference/basic_socket_acceptor/local_endpoint/overload1.html

Example demonstrating how to get the local endpoint of a boost::asio::ip::tcp::acceptor.

```cpp
boost::asio::ip::tcp::acceptor acceptor(my_context);
...
boost::asio::ip::tcp::endpoint endpoint = acceptor.local_endpoint();

```

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

### Main Function Setup and Execution

Source: https://www.boost.org/doc/libs/latest/doc/html/boost_asio/example/cpp17/coroutines_ts/range_based_for.cpp

Sets up the Boost.Asio io_context, signal handling for graceful shutdown, a TCP acceptor on port 55555, and spawns the listener coroutine. It then runs the io_context to process events.

```cpp
int main()
{
  try
  {
    boost::asio::io_context io_context(1);

    boost::asio::signal_set signals(io_context, SIGINT, SIGTERM);
    signals.async_wait([&](auto, auto){ io_context.stop(); });

    tcp::acceptor acceptor(io_context, {tcp::v4(), 55555});
    co_spawn(io_context, listener(std::move(acceptor)), detached);

    io_context.run();
  }
  catch (std::exception& e)
  {
    std::printf("Exception: %s\n", e.what());
  }
}
```

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

### Get the first character of a decode_view

Source: https://www.boost.org/doc/libs/latest/doc/antora/url/reference/boost/urls/decode_view/front.html

This example shows how to get the first character of a decoded URL string view using `front()`.

```cpp
assert( decode_view( "Program%20Files" ).front() == 'P' );
```

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

### Main Server Loop and Initialization

Source: https://www.boost.org/doc/libs/latest/libs/beast/example/websocket/server/sync-ssl/websocket_server_sync_ssl.cpp

This is the main function that sets up the server. It parses command-line arguments for address and port, initializes the io_context and SSL context, loads the server certificate, and then enters an infinite loop to accept incoming connections and launch new sessions in separate threads.

```cpp
int main(int argc, char* argv[])
{
    try
    {
        // Check command line arguments.
        if (argc != 3)
        {
            std::cerr <<
                "Usage: websocket-server-sync-ssl <address> <port>\n" <<
                "Example:\n" <<
                "    websocket-server-sync-ssl 0.0.0.0 8080\n";
            return EXIT_FAILURE;
        }
        auto const address = net::ip::make_address(argv[1]);
        auto const port = static_cast<unsigned short>(std::atoi(argv[2]));

        // The io_context is required for all I/O
        net::io_context ioc{1};

        // The SSL context is required, and holds certificates
        ssl::context ctx{ssl::context::tlsv12};

        // This holds the self-signed certificate used by the server
        load_server_certificate(ctx);

        // The acceptor receives incoming connections
        tcp::acceptor acceptor{ioc, {address, port}};
        for(;;)
        {
            // This will receive the new connection
            tcp::socket socket{ioc};

            // Block until we get a connection
            acceptor.accept(socket);

            // Launch the session, transferring ownership of the socket
            std::thread(
                &do_session,
                std::move(socket),
                std::ref(ctx)).detach();
        }
    }
    catch (const std::exception& e)
    {
        std::cerr << "Error: " << e.what() << std::endl;
        return EXIT_FAILURE;
    }
}
```

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

### Foldr Example Setup

Source: https://www.boost.org/doc/libs/latest/doc/html/metaparse/reference.html

Provides a minimal setup for using the foldr combinator, defining an integer token and a sum operation metafunction.

```c++
using int_token = token<int_>;
using sum_op = mpl::lambda<mpl::plus<mpl::_1, mpl::_2>>::type;

```

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

### Boost Hash Map Example

Source: https://www.boost.org/doc/libs/latest/libs/uuid/doc/html/uuid.html

Example demonstrating the use of UUIDs as keys in a boost::unordered_flat_map.

```cpp
boost::unordered_flat_map<boost::uuids::uuid, int> hash_map;
```

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

### Main Server Entry Point

Source: https://www.boost.org/doc/libs/latest/libs/beast/example/advanced/server-flex/advanced_server_flex.cpp

Parses command-line arguments for address, port, document root, and thread count. Initializes the io_context, SSL context, loads the server certificate, and starts the listener. Sets up signal handling for graceful shutdown.

```cpp
int main(int argc, char* argv[])
{
    // Check command line arguments.
    if (argc != 5)
    {
        std::cerr <<
            "Usage: advanced-server-flex <address> <port> <doc_root> <threads>\n" <<
            "Example:\n" <<
            "    advanced-server-flex 0.0.0.0 8080 . 1\n";
        return EXIT_FAILURE;
    }
    auto const address = net::ip::make_address(argv[1]);
    auto const port = static_cast<unsigned short>(std::atoi(argv[2]));
    auto const doc_root = std::make_shared<std::string>(argv[3]);
    auto const threads = std::max<int>(1, std::atoi(argv[4]));

    // The io_context is required for all I/O
    net::io_context ioc{threads};

    // The SSL context is required, and holds certificates
    ssl::context ctx{ssl::context::tlsv12};

    // This holds the self-signed certificate used by the server
    load_server_certificate(ctx);

    // Create and launch a listening port
    std::make_shared<listener>(
        ioc,
        ctx,
        tcp::endpoint{address, port},
        doc_root)->run();

    // Capture SIGINT and SIGTERM to perform a clean shutdown
    net::signal_set signals(ioc, SIGINT, SIGTERM);
    signals.async_wait(
        [&](beast::error_code const&, int) 
        {
            // Stop the `io_context`. This will cause `run()`
            // to return immediately, eventually destroying the
            // `io_context` and all of the sockets in it.
            ioc.stop();
        });

    // Run the I/O service on the requested number of threads
    std::vector<std::thread> v;
    v.reserve(threads - 1);
    for(auto i = threads - 1; i > 0; --i)
        v.emplace_back(
        [&ioc]
        {
            ioc.run();
        });
    ioc.run();

    // (If we get here, it means we got a SIGINT or SIGTERM)

    // Block until all the threads exit
    for(auto& t : v)
        t.join();

    return EXIT_SUCCESS;
}
```

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

### Get Device Info Example (CL_DEVICE_MAX_COMPUTE_UNITS)

Source: https://www.boost.org/doc/libs/latest/libs/compute/doc/html/doxygen/header_reference/classboost_1_1compute_1_1device.html

Example of how to retrieve the maximum number of compute units for a device using `get_info` with a specific type.

```cpp
device.get_info<cl_uint>(CL_DEVICE_MAX_COMPUTE_UNITS);
```

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

### In-place Construction Framework Example

Source: https://www.boost.org/doc/libs/latest/libs/utility/doc/html/utility/utilities/in_place_factory.html

A simplified example demonstrating the core idea of the In-place Factory framework, where a container uses a factory to construct an object directly in its storage.

```cpp
struct C
{
   template <class InPlaceFactory>
   C ( InPlaceFactory const& aFactory )
    :
    contained_ ( uninitialized_storage() )
   {
     aFactory.template apply<X>(contained_);
   }

  ~C()
  {
    contained_ -> X::~X();
    delete[] contained_ ;
  }

  char* uninitialized_storage() { return new char[sizeof(X)] ; }

  char* contained_ ;
};

void foo()
{
  C c( in_place(123,"hello") ) ;
}

```

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

### foldl_reject_incomplete_start_with_parser Example Setup

Source: https://www.boost.org/doc/libs/latest/doc/html/metaparse/reference.html

Sets up example parsers and operations for demonstrating foldl_reject_incomplete_start_with_parser, including integer tokens, plus tokens, and a sum operation.

```c++
using int_token = token<int_>;
using plus_token = token<lit_c<'+'>>;
using plus_int = last_of<plus_token, int_token>;
using sum_op = mpl::lambda<mpl::plus<mpl::_1, mpl::_2>>::type;
```