Header Organization and Compiled Binaries

This section covers the basics of the organization of Boost libraries in the folder structure, a list of libraries requiring compilation into binaries, or optionally using compilation, and the tools which you might use to compile the headers.

Header Organization

The organization of Boost library headers isn’t entirely uniform, but most libraries follow a few patterns:

  • Some older libraries and most very small libraries place all public headers directly into Boost.

  • Most libraries' public headers live in a subdirectory of boost, named after the library. For example, you’ll find the Python library’s def.hpp header in boost/python/def.hpp.

  • Some libraries have an “aggregate header” in boost that includes all of the library’s other headers. For example, Boost.Python's aggregate header is boost/python.hpp.

  • Most libraries place private headers in a subdirectory called detail, or aux. Don’t expect to find anything you can use in these directories.

It’s important to note the following:

  1. The path to the boost root directory (often /usr/local/boost_1_82_0) is sometimes referred to as $BOOST_ROOT in documentation and mailing lists.

  2. To compile anything in Boost, you need a directory containing the boost subdirectory in your #include path.

  3. Since all of Boost’s header files have the .hpp extension, and live in the boost subdirectory of the boost root, your Boost #include directives will look like: #include <boost/whatever.hpp> or #include "boost/whatever.hpp", depending on your preference regarding the use of angle bracket includes.

  4. Don’t be distracted by the doc subdirectory; it only contains a subset of the Boost documentation. Start with libs/index.html if you’re looking for the whole enchilada.

Required Compiled Binaries

Most Boost libraries are header-only: they consist entirely of header files containing templates and inline functions, and require no separately-compiled library binaries or special treatment when linking.

The only Boost libraries that must be built separately are:

Optional Compiled Binaries

A few libraries have optional separately-compiled binaries:

  • Boost.Exception provides non-intrusive implementation of exception_ptr for 32-bit _MSC_VER==1310 and _MSC_VER==1400 which requires a separately-compiled binary. This is enabled by #define BOOST_ENABLE_NON_INTRUSIVE_EXCEPTION_PTR.

  • Boost.Graph also has a binary component that is only needed if you intend to parse GraphViz files.

  • Boost.Math has binary components for the TR1 and C99 cmath functions.

  • Boost.Random has a binary component which is only needed if you’re using random_device.

  • Boost.System is header-only since Boost 1.69. A stub library is still built for compatibility, but linking to it is no longer necessary.

  • Boost.Test can be used in “header-only” or “separately compiled” mode, although separate compilation is recommended for serious use.

Identify Your Toolset

In order to build binaries from source, find the toolset corresponding to your compiler in the following table (an up-to-date list is also available in Builtin tools).


If you previously chose a toolset for the purposes of building b2, you should assume it won’t work and instead choose newly from the table below.

Toolset Name Vendor Notes


Hewlett Packard

Only very recent versions are known to work well with Boost




Comeau Computing

Using this toolset may require configuring another toolset to act as its backend.


Apple Computer

Apple’s version of the GCC toolchain with support for Darwin and MacOS X features such as frameworks.


The Gnu Project

Includes support for Cygwin and MinGW compilers.


Hewlett Packard

Targeted at the Tru64 operating system.







Only very recent versions are known to work well with Boost. Note that the Oracle/Sun compiler has a large number of options which effect binary compatibility. It is vital that the libraries are built with the same options that your application will use. In particular be aware that the default standard library may not work well with Boost, unless you are building for Cpp11.

The particular compiler options you need can be injected with the b2 command line options cxxflags= and linkflags=. For example to build with the Apache standard library in Cpp03 mode use:

b2 cxxflags=-library=stdcxx4 linkflags=-library=stdcxx4.



The VisualAge C++ compiler.

If you have multiple versions of a particular compiler installed, you can append the version number to the toolset name, preceded by a hyphen, e.g. intel-9.0 or borland-5.4.3.

On Windows, append a version number even if you only have one version installed (unless you are using the msvc or gcc toolsets, which have special version detection code) or auto-linking will fail.