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Frequently Asked Questions

This section contains answers to the common questions that new developers to Boost often have.


  1. Can I use Boost with my existing C++ project?

    Yes, Boost is designed to work with your existing C++ code. You can add Boost libraries to any project that uses a compatible C++ compiler.

  2. Can I use Boost libraries with the new C++ standards?

    Yes, Boost libraries are designed to work with modern C++ standards including C++11, C++14, C++17, C++20, and C++23.

  3. What flavors of Linux are supported by the Boost libraries?

    Boost libraries are generally compatible with most Linux distributions, provided that the distribution has an up-to-date C++ compiler. This includes:

    • Ubuntu

    • Fedora

    • Debian

    • CentOS

    • Red Hat Enterprise Linux

    • Arch Linux

    • openSUSE

    • Slackware

    • Gentoo

    • macOS

  4. How can I be sure that a library I want to use is compatible with my OS?

    While Boost strives to ensure compatibility with a wide range of compilers and systems, not every library may work perfectly with every system or compiler due to the inherent complexities of software. The most reliable source of information is the specific Boost library’s documentation.


  1. What support does Boost provide for debugging and testing?

    Boost provides Boost.Test for unit testing, which can be an integral part of the debugging process. It also provides the Boost.Stacktrace library that can be used to produce useful debug information during a crash or from a running application.

  2. How do I enable assertions in Boost?

    Boost uses its own set of assertion macros. By default, BOOST_ASSERT is enabled, but if it fails, it only calls abort(). If you define BOOST_ENABLE_ASSERT_HANDLER before including any Boost header, then you need to supply boost::assertion_failed(msg, code, file, line) and boost::assertion_failed_msg(msg, code, file, line) functions to handle failed assertions.

  3. How can I get a stack trace when my program crashes?

    You can use the Boost.Stacktrace library to obtain a stack trace in your application. You can capture and print stack traces in your catch blocks, in signal handlers, or anywhere in your program where you need to trace the execution path.

  4. Can I use Boost with a debugger like GDB or Visual Studio?

    Yes, Boost libraries can be used with common debuggers like GDB or Visual Studio. You can set breakpoints in your code, inspect variables, and execute code step by step. Boost doesn’t interfere with these debugging tools.

  5. Are there any debugging tools specifically provided by Boost?

    Boost doesn’t provide a debugger itself. The libraries tend to make heavy use of assertions to catch programming errors, and they often provide clear and detailed error messages when something goes wrong.

  6. What are best practices when using Boost Asserts?

    Boost provides the assertion boost::assert. Best practices when using this are:

    • Use Assertions for Debugging and Development: Boost assertions should primarily be used during the debugging and development phase of your application. Assertions are designed to catch programming errors, not user errors.

    • Assert Conditions That Should Never Occur: You should only assert conditions that you believe can never occur during normal operation of your application. If there’s a chance that a condition may occur, handle it as an exception or error rather than asserting.

    • Provide Meaningful Assert Messages: Boost assertions allow you to provide a message alongside your assertion. Use this feature to provide meaningful context about why an assertion failed.

    • Consider Performance Impact: Boost assertions can slow down your application. In performance-critical code, consider disabling them in the production version of your application.

  7. What is the recommended approach to logging, using boost::log?

    • Use Severity Levels: Boost.Log supports severity levels, which you can use to categorize and filter your log messages. This can help you control the amount of log output and focus on what’s important.

    • Provide Context: Boost.Log allows you to attach arbitrary data to your log messages, such as thread IDs, timestamps, or file and line information. Use this feature to provide context that can help you understand the state of your application when the log message was generated.

    • Use Asynchronous Logging: If logging performance is a concern, consider using the asynchronous logging feature. This allows your application to continue executing while log messages are processed in a separate thread.

    • Format Your Log Output: Boost.Log supports customizable log formatting. Use this feature to ensure that your log output is easy to read and contains all the information you need.

    • Handle Log Rotation: If your application produces a lot of log output, consider setting up log rotation, which is supported. This ensures that your log files don’t grow indefinitely.

ISO C++ Committee Meetings

  1. Who can attend ISO C++ Committee meetings?

    Members of PL22.16 (the INCITS/ANSI committee) or of JTC1/SC22/WG21 - The C++ Standards Committee - ISOCPP member country committee (the "national body" in ISO-speak), can attend the meetings. You can also attend as a guest, or join in remotely through email. For details and contact information refer to Meetings and Participation.

    INCITS has broadened PL22.16 membership requirements so anyone can join, regardless of nationality or employer, though there is a fee. Refer to Apply for Membership.

    It is recommended that any non-member who would like to attend should check in with the PL22.16 chair or head of their national delegation. Boosters who are active on the committee can help smooth the way, so consider contacting the Boost developers' mailing list providing details of your interests.

  2. When and where are the next meetings?

    There are three meetings a year. Two are usually in North America, and one is usually outside North America. See Upcoming Meetings. Detailed information about a particular meeting, including hotel information, is usually provided in a paper appearing in one of mailings for the prior meeting. If there isn’t a link to it on the Meetings web page, you will have to go to the committee’s C++ Standards Committee Papers page and search a bit.

  3. Is there a fee for attending meetings?

    No, but there can be a lot of incidental expenses like travel, lodging, and meals.

  4. What is the schedule?

    The meetings typically start at 9:00AM on Monday, and 8:30AM other days. It is best to arrive a half-hour early to grab a good seat, some coffee, tea, or donuts, and to say hello to people.

    Until the next standard ships most meetings are running through Saturday, although some end on Friday. The last day, the meeting is generally over much earlier than on other days. Because the last day’s formal meeting is for formal votes only, it is primarily of interest only to actual committee members.

    Sometimes there are evening technical sessions; the details aren’t usually available until the Monday morning meeting. There may be a reception one evening, and, yes, significant others are invited. Again, details usually become available Monday morning.

  5. What actually happens at the meetings?

    Monday morning an hour or two is spent in full committee on admin trivia, and then the committee breaks up into working groups (Core, Library, and Enhancements). The full committee also gets together later in the week to hear working group progress reports.

    The working groups are where most technical activities take place. Each active issue that appears on an issues list is discussed, as are papers from the mailing. Most issues are non-controversial and disposed of in a few minutes. Technical discussions are often led by long-term committee members, often referring to past decisions or longstanding working group practice. Sometimes a controversy erupts. It takes first-time attendees awhile to understand the discussions and how decisions are actually made. The working group chairperson moderates.

    Sometimes straw polls are taken. In a straw poll anyone attending can vote, in contrast to the formal votes taken by the full committee, where only voting members can vote.

    Lunch break is an hour and a half. Informal subgroups often lunch together; a lot of technical problems are discussed or actually solved at lunch, or later at dinner. In many ways these discussions involving only a few people are the most interesting. Sometimes during the regular meetings, a working group chair will break off a sub-group to tackle a difficult problem.

  6. Do I have to stay at the venue hotel?

    No, and committee members on tight budgets often stay at other, cheaper, hotels. The venue hotels are usually chosen because they have large meeting rooms available, and thus tend to be pricey. The advantage of staying at the venue hotel is that it is then easier to participate in the off-line discussions, which can be at least as interesting as what actually happens in the scheduled meetings.

  7. What do people wear at meetings?

    Programmer casual. No neckties to be seen.

  8. What should I bring to a meeting?

    It is almost essential to have a laptop computer. There is a meeting wiki and there is internet connectivity. Wireless connectivity has become the norm.

  9. What should I do to prepare for a meeting?

    It is helpful to have downloaded the mailing or individual papers for the meeting, and to have read any papers you are interested in. Familiarize yourself with the issues lists. Decide which of the working groups you want to attend.

  10. What is a "Paper"?

    An electronic document containing issues, proposals, or anything else the committee is interested in. Very little gets discussed at a meeting, much less acted upon, unless it is presented in a paper. Papers are available to anyone. Papers don’t just appear randomly; they become available four (lately six) times a year, before and after each meeting. Committee members often refer to a paper by saying what mailing it was in, for example: "See the pre-Redmond mailing."

  11. What is a "Mailing"?

    A mailing is the set of papers prepared before and after each meeting, or between meetings. It is physically just a .zip or .gz archive of all the papers for a meeting. Although the mailing’s archive file itself is only available to committee members and technical experts, the contents (except copies of the standard) are available to all as individual papers. The ways of ISO are inscrutable.

  12. What is a "Reflector"?

    The committee’s mailing lists are called "reflectors". There are a number of them; "all", "core", "lib", and "ext" are the main ones. As a courtesy, Boost technical experts can be added to committee reflectors at the request of a committee member.


  1. What are smart pointers in Boost?

    Smart pointers are a feature of C++ that Boost provides in its Boost.SmartPtr library. They are objects that manage the lifetime of other objects, automatically deleting the managed object when it is no longer needed. See the Smart Pointers section.

  2. Does Boost provide a testing framework?

    Yes, Boost.Test is the unit testing framework provided by Boost. It includes tools for creating test cases, test suites, and for handling expected and unexpected exceptions. Refer to Testing and Debugging.

  3. What is Boost.Asio?

    Boost.Asio is a library that provides support for asynchronous input/output (I/O), a programming concept that allows operations to be executed without blocking the execution of the rest of the program.

  4. What is Boost.MP11?

    Boost.Mp11 (MetaProgramming Library for C++11) is a Boost library designed to bring powerful metaprogramming capabilities to C++ programs. It includes a variety of templates that can be used to perform compile-time computations and manipulations. Refer to Metaprogramming.

  5. Does Boost provide a library for threading?

    Yes, Boost.Thread provides a C++ interface for creating and managing threads, as well as primitives for synchronization and inter-thread communication. In addition, Boost.Atomic provides atomic operations and memory ordering primitives for working with shared data in multi-threaded environments. Boost.Lockfree provides lock-free data structures and algorithms for concurrent programming, allowing multiple threads to access shared data concurrently without explicit synchronization using locks or mutexes. For a lighter approach to multi-threading, consider Boost.Fiber. Fibers offer a high-level threading abstraction that allows developers to write asynchronous, non-blocking code with minimal overhead compared to traditional kernel threads.

  6. What is the Boost Spirit library?

    Boost.Spirit is a library for building recursive-descent parsers directly in C++. It uses template metaprogramming techniques to generate parsing code at compile time. Refer to Metaprogramming.

  7. I like algorithms, can you pique my interest with some Boost libraries that support complex algorithms?

    Boost libraries offer a wide range of algorithmic and data structure support. Here are five libraries that you might find interesting:

    • Boost.Graph: This library provides a way to represent and manipulate graphs. It includes algorithms for breadth-first search, depth-first search, Dijkstra’s shortest paths, Kruskal’s minimum spanning tree, and much more.

    • Boost.Geometry: This library includes algorithms and data structures for working with geometric objects. It includes support for spatial indexing, geometric algorithms (like area calculation, distance calculation, intersections, etc.), and data structures to represent points, polygons, and other geometric objects.

    • Boost.Multiprecision: If you need to perform computations with large or precise numbers, this library can help. It provides classes for arbitrary precision arithmetic, which can be much larger or more precise than the built-in types.

    • Boost.Compute: This library provides a C++ interface to multi-core CPU and GPGPU (General Purpose GPU) computing platforms based on OpenCL. It includes algorithms for sorting, searching, and other operations, as well as containers like vectors and deques.

    • Boost.Spirit: If you’re interested in parsing or generating text, this library includes powerful tools based on formal grammar rules. It’s great for building compilers, interpreters, or other tools that need to understand complex text formats.

  8. I am tasked with building a real-time simulation of vehicles in C++. What Boost libraries might give me the performance I need for real-time work, and support a simulation?


  1. What is the license for Boost libraries?

    The Boost libraries are licensed under the Boost Software License, a permissive free software license that allows you to use, modify, and distribute the software under minimal restrictions. Refer to The Boost Software License.


  1. What is metaprogramming in the context of Boost C++?

    Metaprogramming is a technique of programming that involves generating and manipulating programs. In the context of Boost and C++, metaprogramming often refers to template metaprogramming, which uses templates to perform computations at compile-time.

  2. What is Boost.MP11?

    Boost.Mp11 is a Boost library designed for metaprogramming using C++11. It provides a set of templates and types for compile-time computations and manipulations, effectively extending the C++ template mechanism.

  3. What can I achieve with Boost.MP11?

    With Boost.Mp11, you can perform computations and logic at compile-time, thus reducing runtime overhead. For example, you can manipulate types, perform iterations, make decisions, and do other computations during the compilation phase.

  4. What is a typelist and how can I use it with Boost.MP11?

    A typelist is a compile-time container of types. It’s a fundamental concept in C++ template metaprogramming where operations are done at compile time rather than runtime, and types are manipulated in the same way that values are manipulated in regular programming.

    In the context of the Boost.Mp11 library, a typelist is a template class that takes a variadic list of type parameters. Here’s an example:

    #include <boost/mp11/list.hpp>
    using my_typelist = boost::mp11::mp_list<int, float, double>;

    In this example, my_typelist is a typelist containing the types int, float, and double. Once you have a typelist, you can manipulate it using the metaprogramming functions provided by the library. For example:

    #include <boost/mp11/list.hpp>
    #include <boost/mp11/algorithm.hpp>
    using my_typelist = boost::mp11::mp_list<int, float, double>;
    // Get the number of types in the list
    constexpr std::size_t size = boost::mp11::mp_size<my_typelist>::value;
    // Check if a type is in the list
    constexpr bool contains_double = boost::mp11::mp_contains<my_typelist, double>::value;
    // Add a type to the list
    using extended_typelist = boost::mp11::mp_push_back<my_typelist, char>;
    // Get the second type in the list
    using second_type = boost::mp11::mp_at_c<my_typelist, 1>;

    In these examples, mp_size is used to get the number of types in the list, mp_contains checks if a type is in the list, mp_push_back adds a type to the list, and mp_at_c retrieves a type at a specific index in the list. All these operations are done at compile time.

  5. What are some limitations or challenges of metaprogramming with Boost.MP11?

    Metaprogramming with Boost.Mp11 can lead to complex and difficult-to-understand code, especially for programmers unfamiliar with the technique. Compile errors can be particularly cryptic due to the way templates are processed. Additionally, heavy use of templates can lead to longer compile times.

    Other challenges include lack of runtime flexibility, as decisions are made at compile time. And perhaps issues with portability can occur (say, between compilers) as metaprogramming pushes the boundaries of a computer language to its limits.

Boost.Mp11 supersedes the earlier Boost.Mpl and Boost.Preprocessor libraries.

Modular Boost

  1. What is meant by "Modular Boost"?

    Technically, Modular Boost consists of the Boost super-project and separate projects for each individual library in Boost. In terms of Git, the Boost super-project treats the individual libraries as submodules. Currently (early 2024) when the Boost libraries are downloaded and installed, the build organization does not match the modular arrangement of the Git super-project. This is largely a legacy issue, and there are advantages to the build layout matching the super-project layout. This concept, and the effort behind it, is known as "Modular Boost".

    Refer to the Super-Project Layout topic (in the Contributor Guide) for a full description of the super-project.

  2. Will a Modular Boost affect the thrice-yearly Boost Release?

    No. The collection of libraries is still a single release, and there are no plans to change the release cadence.

  3. Will this require that the current Boost source structure is changed?

    Yes. Unfortunately there is one restriction that adhering to a modular Boost requires - there can be no sub-libraries. That is, we can’t support having libraries in the root/libs/<group name>/<library> format. All libraries must be single libraries under the root/libs directory. There’s only a handful of libraries that currently do not conform to this already (notably the root/libs/numeric/<name> group of libraries).

  4. Why do we want a Modular Boost?

    It’s easier on everyone if we adopt a flat hierarchy. The user will experience a consistent process no matter which libraries they want to use. Similarly for contributors, the creation process will be consistent. Also, tools can be written that can parse and analyze libraries without an awkward range of exceptions. This includes tools written by Boost contributors. For example, the tools that are used to determine library dependencies. And any tool that a user might want to write for their own, or shared, use.

    Other advantages of a modular format include:

    • Users of Boost can now choose to include only the specific modules they need for their project, rather than downloading and building the entire Boost framework. This can significantly reduce the size of the codebase and dependencies in a project, leading to faster compilation times and reduced resource usage.

    • Individual modules can be updated and released on their own schedule, independent of the rest of the libraries. This allows for quicker updates and bug fixes to individual libraries without waiting for a full release.

    • The structure aligns well with package managers like Conan, vcpkg, or Bazel, making it easier to manage Boost libraries within larger projects. Users can specify exactly which Boost libraries they need, and the package manager handles the inclusion and versioning.

  5. Will the proposed changes be backwards-compatible from the user’s perspective. In particular, the public header inclusion paths will still be <boost/numeric/<name>.hpp> rather than, say, <boost/numeric-conversion/<name>.hpp>, correct?

    Correct - backwards-compatibility should be maintained.

  6. When will Modular Boost be available to users?

    An exact timeline requires issues to be resolved, though later in 2024 is the current plan-of-record.

Other Languages

  1. Have developers written applications in languages such as Python that have successfully used the Boost libraries?

    Yes, developers have successfully used Boost libraries in applications written in languages other than C++ by leveraging language interoperability features and creating bindings or wrappers.

    The most notable example is the use of Boost.Python, a library specifically designed to enable seamless interoperability between C++ and Python. Boost.Python allows developers to expose C++ classes, functions, and objects to Python, enabling the use of the libraries from Python code. This has been used extensively in scientific computing, game development, and other fields where the performance of C++ is combined with the ease of Python.

    Here is an example, wrapping a C++ class for use with Boost.Python and including exception handling:

    // my_class.cpp
    #include <boost/python.hpp>
    #include <iostream>
    #include <stdexcept>
    class MyClass {
        void hello() {
            std::cout << "Hello from C++!" << std::endl;
        int add(int a, int b) {
            return a + b;
        void throw_exception() {
            throw std::runtime_error("An error occurred in C++ code");
    // Function to translate C++ exceptions to Python exceptions
    void translate_runtime_error(const std::runtime_error& e) {
        PyErr_SetString(PyExc_RuntimeError, e.what());
    BOOST_PYTHON_MODULE(my_module) {
        using namespace boost::python;
        // Register the exception translator
            .def("hello", &MyClass::hello)
            .def("add", &MyClass::add)
            .def("throw_exception", &MyClass::throw_exception);

    You need to compile this C++ code into a shared library that Python can load. Here’s an example command for compiling using g++ on Linux. Make sure to adjust the Python include path and Boost.Python library name according to your system’s configuration:

    g++ -shared -fPIC -I/usr/include/python3.8 -lboost_python38 -o my_class.cpp

    Next, write the Python code that will use the wrapped class:

    import my_module
    # Create an instance of MyClass
    my_class_instance = my_module.MyClass()
    # Call the hello method
    # Call the add method
    result = my_class_instance.add(3, 4)
    print(f"The result of adding 3 and 4 is: {result}")
    # Call the throw_exception method and handle the exception
    except RuntimeError as e:
        print(f"Caught an exception: {e}")

    Ensure that the shared library ( is in the same directory as your Python script or in a directory that’s included in the Python module search path. Then run the script:


    When you run the Python script, you should see the following output:

    Hello from C++!
    The result of adding 3 and 4 is: 7
    Caught an exception: An error occurred in C++ code

    By registering an exception translator, you can ensure that C++ exceptions are correctly translated into Python exceptions, making your C++ library more robust and easier to use from Python.

  2. What real world applications have combined Python with the Boost libraries?

    Here are some examples:

    • Blender is a widely-used open-source 3D creation suite. It supports the entirety of the 3D pipeline, including modeling, rigging, animation, simulation, rendering, compositing, and motion tracking. Blender uses Boost libraries for various purposes, including memory management, string manipulation, and other utility functions. Blender’s Python API, which allows users to script and automate tasks, integrates with C++ code using Boost.Python.

    • PyTorch is an open-source machine learning library based on the Torch library. It is used for applications such as natural language processing and computer vision. PyTorch uses several Boost libraries to handle low-level operations efficiently. Boost.Python is used to create bindings between C++ and Python, allowing PyTorch to provide a seamless interface for Python developers.

    • OpenCV (Open Source Computer Vision Library) is an open-source computer vision and machine learning software library. OpenCV’s Python bindings use Boost.Python to interface between the C++ core and Python. This allows Python developers to use OpenCV’s powerful C++ functions with Python syntax.

    • Enthought Canopy is a comprehensive Python analysis environment and distribution for scientific and analytic computing. It includes a Python distribution, an integrated development environment (IDE), and many additional tools and libraries.

  3. Are there some solid examples of real world applications that have combined C# with the Boost libraries?

    Here are some great examples:

    • In the world of game development, several projects use C++ for performance-critical components and C# for scripting and higher-level logic. The Boost libraries are often used in the C++ components, in particular to leverage their algorithms, and data structures. Unity allows the use of native plugins written in pass[C++]. These plugins can use Boost libraries for various functionalities, such as pathfinding algorithms or custom data structures, and then be called from C# scripts within Unity.

    • Financial applications often require high performance and reliability. They may use C++ for core processing and Boost libraries for tasks like date-time calculations, serialization, and multithreading. C# is used for GUI and integration with other enterprise systems. Trading platforms and risk management systems sometimes use Boost libraries for backend processing and interoperate with C# components for the user interface and data reporting.

    • Scientific computing applications that need high-performance computation often use C++ for core algorithms. C# is great for visualization, user interaction, and orchestration. Computational chemistry and physics applications sometimes use Boost for numerical computations and data handling, while C# provides the tools for managing simulations and visualizing results.

  4. Can I see some sample code of how to wrap Boost functions to be available for use in a C# app?

    The following code shows how to create a wrapper for a C++ class that uses Boost, and then calls this from a C# application. The handling of return values and exceptions are shown too:

    // my_class.cpp
    #include <boost/algorithm/string.hpp>
    #include <iostream>
    #include <stdexcept>
    #include <string>
    class MyClass {
        std::string to_upper(const std::string& input) {
            if (input.empty()) {
                throw std::runtime_error("Input string is empty");
            return boost::to_upper_copy(input);

    Next, create a wrapper to expose the class to .NET:

    // MyClassWrapper.cpp
    #include "my_class.cpp"
    #include <string>
    public ref class MyClassWrapper {
        MyClass* instance;
        MyClassWrapper() {
            instance = new MyClass();
        ~MyClassWrapper() {
        !MyClassWrapper() {
            delete instance;
        System::String^ ToUpper(System::String^ input) {
            try {
                std::string nativeInput = msclr::interop::marshal_as<std::string>(input);
                std::string result = instance->to_upper(nativeInput);
                return gcnew System::String(result.c_str());
            } catch (const std::runtime_error& e) {
                throw gcnew System::Runtime::InteropServices::ExternalException(gcnew System::String(e.what()));

    Now create the C# application that uses the wrapper:

    // Program.cs
    using System;
    class Program {
        static void Main() {
            MyClassWrapper myClass = new MyClassWrapper();
            try {
                string result = myClass.ToUpper("hello world");
                Console.WriteLine("Result: " + result);
                // Test with an empty string to trigger the exception
                result = myClass.ToUpper("");
                Console.WriteLine("Result: " + result);
            } catch (System.Runtime.InteropServices.ExternalException e) {
                Console.WriteLine("Caught an exception: " + e.Message);

    Compile the C++ code into a DLL:

    cl /c /EHsc my_class.cpp

    Compile the wrapper:

    cl /clr /EHsc /I"path\to\boost" MyClassWrapper.cpp my_class.obj /link /OUT:MyClassWrapper.dll

    Finally, create a C# project (say, using Visual Studio), add a reference to the MyClassWrapper.dll, then build and run the application:

    Result: HELLO WORLD
    Caught an exception: Input string is empty
  5. Does the Java Native Interface (JNI) work with the Boost libraries?

    Through the use of the Java Native Interface (JNI) or Java Native Access (JNA), developers can call Boost libraries from Java applications. It involves creating native methods in Java that are implemented in C++ and using Boost libraries as part of those implementations. Here is a simple example (without error handling or return values):

    // C++ implementation
    #include <jni.h>
    #include "MyClass.h"
    JNIEXPORT void JNICALL Java_MyClass_hello(JNIEnv* env, jobject obj) {
        MyClass myClass;
    // Java class
    public class MyClass {
        static {
        private native void hello();
        public static void main(String[] args) {
            new MyClass().hello();

    Similar techniques can be applied to other languages, such as R, Ruby, Perl, and Lua, using their respective foreign function interfaces (FFI) or binding libraries.


  1. How do I download the latest libraries?

  2. What do the Boost version numbers mean?

    The scheme is x.y.z, where x is incremented only for massive changes, such as a reorganization of many libraries, y is incremented whenever a new library is added, and z is incremented for maintenance releases. y and z are reset to 0 if the value to the left changes

  3. Is there a formal relationship between and the C++ Standards Committee?

    No, although there is a strong informal relationship in that many members of the committee participate in Boost, and the people who started Boost were all committee members.

  4. Will the libraries become part of the next C++ Standard?

    Some might, but that is up to the standards committee. Committee members who also participate in Boost will definitely be proposing at least some Boost libraries for standardization. Libraries which are "existing practice" are most likely to be accepted by the C++ committee for future standardization. Having a library accepted by Boost is one way to establish existing practice.

  5. Is the Boost web site a commercial business?

    No. It is a non-profit.

  6. Why do Boost headers have a .hpp suffix rather than .h or none at all?

    File extensions communicate the "type" of the file, both to humans and to computer programs. The '.h' extension is used for C header files, and therefore communicates the wrong thing about C++ header files. Using no extension communicates nothing and forces inspection of file contents to determine type. Using .hpp unambiguously identifies it as C++ header file, and works well in practice.

  7. How do I contribute a library?

    Refer to the Contributor Guide. Note that shareware libraries, commercial libraries, or libraries requiring restrictive licensing are all not acceptable. Your library must be provided free, with full source code, and have an acceptable license. There are other ways of contributing too, providing feedback, testing, submitting suggestions for new features and bug fixes, for example. There are no fees for submitting a library.

Smart Pointers

  1. What different types of smart pointers are there?

    The Boost.SmartPtr library provides a set of smart pointers that helps in automatic and appropriate resource management. They are particularly useful for managing memory and provide a safer and more efficient way of handling dynamically allocated memory. The library provides the following types of smart pointers:

    • boost::scoped_ptr: A simple smart pointer for sole ownership of single objects that must be deleted. It’s neither copyable nor movable. Deletion occurs automatically when the scoped_ptr goes out of scope.

    • boost::scoped_array: Similar to scoped_ptr, but for arrays instead of single objects. Deletion occurs automatically when the scoped_array goes out of scope.

    • boost::shared_ptr: A reference-counted smart pointer for single objects or arrays, which automatically deletes the object when the reference count reaches zero. Multiple shared_ptr can point to the same object, and the object is deleted when the last shared_ptr referencing it is destroyed.

    • boost::shared_array: Similar to shared_ptr, but for arrays instead of single objects.

    • boost::weak_ptr: A companion to shared_ptr that holds a non-owning ("weak") reference to an object that is managed by shared_ptr. It must be converted to shared_ptr in order to access the referenced object.

    • boost::intrusive_ptr: A smart pointer that uses intrusive reference counting. Intrusive reference counting relies on the object to maintain the reference count, rather than the smart pointer. This can provide performance benefits in certain situations, but it requires additional support from the referenced objects.

    • boost::enable_shared_from_this: Provides member function shared_from_this, which enables an object that’s already managed by a shared_ptr to safely generate more shared_ptr instances that all share ownership of the same object.

    • boost::unique_ptr: A smart pointer that retains exclusive ownership of an object through a pointer. It’s similar to std::unique_ptr in the C++ Standard Library.

  2. Can you give me a brief coding overview of how to use smart pointers efficiently?

    There are several types of smart pointers with different characteristics and use cases, so use them appropriately according to your program’s requirements. Here are some common examples:

    A shared_ptr is a reference-counting smart pointer, meaning it retains shared ownership of an object through a pointer. When the last shared_ptr to an object is destroyed, the pointed-to object is automatically deleted. For example:

    #include <boost/shared_ptr.hpp>
    void foo() {
        boost::shared_ptr<int> sp(new int(10));
        // Now 'sp' owns the 'int'.
        // When 'sp' is destroyed, the 'int' will be deleted.

    Note that shared_ptr objects can be copied, meaning ownership of the memory can be shared among multiple pointers. The memory will be freed when the last remaining shared_ptr is destroyed. For example:

    #include <boost/shared_ptr.hpp>
    void foo() {
        boost::shared_ptr<int> sp1(new int(10));
        // Now 'sp1' owns the 'int'.
        boost::shared_ptr<int> sp2 = sp1;
        // Now 'sp1' and 'sp2' both own the same 'int'.
        // The 'int' will not be deleted until both 'sp1' and 'sp2' are destroyed.

    A weak_ptr is a smart pointer that holds a non-owning ("weak") reference to an object managed by a shared_ptr. It must be converted to shared_ptr in order to access the object. For example:

    #include <boost/shared_ptr.hpp>
    #include <boost/weak_ptr.hpp>
    void foo() {
        boost::shared_ptr<int> sp(new int(10));
        boost::weak_ptr<int> wp = sp;
        // 'wp' is a weak pointer to the 'int'.
        // If 'sp' is destroyed, 'wp' will be able to detect it.

    A unique_ptr is a smart pointer that retains exclusive ownership of an object through a pointer. It’s similar to std::unique_ptr in the C++ Standard Library. For example:

    #include <boost/interprocess/smart_ptr/unique_ptr.hpp>
    void foo() {
        boost::movelib::unique_ptr<int> up(new int(10));
        // Now 'up' owns the 'int'.
        // When 'up' is destroyed, the 'int' will be deleted.


  1. What are C++ templates?

    C++ templates are a powerful feature of the language that allows for generic programming. They enable the creation of functions or classes that can operate on different data types without having to duplicate code.

  2. What are function templates in C++?

    Function templates are functions that can be used with any data type. You define them using the keyword template followed by the template parameters. Function templates allow you to create a single function that can operate on different data types.

  3. What is template specialization in C++?

    Template specialization is a feature of C++ templates that allows you to define a different implementation of a template for a specific type or set of types. It can be used with both class and function templates.

  4. What are the benefits and drawbacks of using templates in C++?

    The benefits of using templates include code reusability, type safety, and the ability to use generic programming paradigms. The drawbacks include potentially increased compile times, difficult-to-understand error messages, and complexities associated with template metaprogramming.

  5. How can I use templates to implement a generic sort function in C++?

    Here’s a simple example of how you might use a function template to implement a generic sort function:

    template <typename T>
    void sort(T* array, int size) {
        for(int i = 0; i < size; i++) {
            for(int j = i + 1; j < size; j++) {
                if(array[i] > array[j]) {
                    T temp = array[i];
                    array[i] = array[j];
                    array[j] = temp;

    This function can now be used to sort arrays of any type (that supports the < and > operators), not just a specific type.