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Boost Frequently Asked Questions

How do I download the libraries?   See Download instructions.

What support is available for the libraries?  The Boost-Users mailing list is a good start.

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. 

Is there any assurance libraries actually work as claimed? No. The review process will hopefully eliminate the most seriously flawed libraries, but a well constructed library with hidden defects is likely to slip through. Encouraging ordinary users to report their experience with a library is intended to address such concerns.  See the Status page for an indication of how well a library works on specific platforms.

How can the Boost libraries be used successfully for important projects?  Many of the Boost libraries are actively maintained and improved, so backward compatibility with prior version isn't always possible. Deal with this by freezing the version of the Boost libraries used by your project. Only upgrade at points in your project's life cycle where a bit of change will not cause problems. Individual bug fixes can always be obtained from the CVS repository.

How is a library accepted for posting on the site? See Library Submission Process

How does someone submit a Formal Review comment?  Send email to  See the Formal Review page for more information.

How does someone submit a library? See Library Guidelines

Are commercial libraries requiring a fee acceptable? No. However, a library that a commercial enterprise makes available without fee is acceptable. If the description of the library makes a low-key plug for the supplier, that is acceptable as long as the library delivers real value and isn't just a Trojan horse for the plug.

Are shareware libraries acceptable? No. Only free libraries will be accepted.

Are open source license libraries acceptable?  Some are, many are not. Open source licenses often require redistribution or availability of source code, inclusion of license document with machine-executable redistribution, give the initial developer rights to licensee modifications, or need a lawyer to understand.  These would be immediate disqualifications for many business, commercial, and consumer applications. Boost aims to avoid subjecting users to hard-to-comply-with license terms. See License requirements.

This is subject to review for a particularly important piece of software, or as the industry changes.

Must full source code be provided? Yes, these are source code libraries.

What about documentation? A very simple library might be accepted with only a well commented header file. For more substantial libraries, some form of documentation is certainly going to be expected.  HTML is the preferred form.

Are platform specific libraries acceptable? There is a preference for portable libraries. Libraries will be accepted that have portable interfaces but require platform specific implementations, as long as the author supplies implementations for a couple of disparate major operating systems.

Must a library do useful work? No. A library meant as a teaching example or demonstration might not actually do any work.

Can an existing library be accepted by Boost? Yes, although it would have to be "Boostified" to meet the requirements.  The Boost Graph and Regex libraries are examples of libraries which began life elsewhere.

Who owns the libraries? Presumably many authors will copyright their libraries. Others authors may wish to place their libraries in the public domain. The policy is to only accept libraries with a clear copyright notice and meeting the License requirements..  It is up to potential users to decide if the terms acceptable, and not to use libraries with unacceptable copyrights or licenses.

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.

Will the libraries become part of the next C++ Standard?  Some might, someday, 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.

Where does the name "Boost" come from? Boost began with Robert Klarer and me fantasizing about a new library effort over dinner at a C++ committee meeting in Sofia Antipolis, France. Robert mentioned that Herb Sutter was working on a spoof proposal for a new language named Booze, which was supposed to be better than Java. Somehow that kicked off the idea of "Boost" as a name. We'd probably had a couple of glasses of good French wine at that point. It was just a working name, but no one ever came up with a replacement. (Beman Dawes)

Is the web site a commercial business? No. It is just some people getting together as a kind of cyberspace civic association. If it ever needs to incorporate, it would be as non-profit organization.

Is there any charge for submitting libraries or reviews to No. Unlike the standards committees, you don't have to pay to volunteer!

Will the site include material beyond libraries? The main focus is on libraries, but if people contribute occasional articles or other material to make the site more interesting, that could be a nice fit.

Why isn't there a separate boost mailing list for my favorite library?  One of the reasons for boost's success has been the cross-pollination of ideas between diverse library projects and the occasional look into other threads by otherwise uninterested parties. The more people participate, the less they tend to be annoyed by "noise".

How can I cope with the large volume of boost mailing list messages?  One approach is to use the YahooGroups digest option; that cuts the email blizzard down to about three (long) messages per day, so you can glance over the subjects summary at the top and quickly read what you think is important. The YahooGroups "no mail/web only" option is best if you just occasionally want to look at messages.

Yet another approach is to use your email program's capabilities to filter messages and automatically transfer them into several boost folders. Then only read the folders you care about. Boost list posters are encouraged to include keywords in the subject like "thread", "review", and "CVS" to aid message filtering.

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 actual practice. (Rainer Deyke)

What should I do if I spot a bug in the Boost code or documentation? See the suggestions on the Bugs page.

How can I request a new feature in a Boost Library? See the Requesting New Features page.

Revised 18 April, 2004

Copyright Beman Dawes 2001

Use, modification, and distribution are subject to the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at