Boost C++ Libraries

...one of the most highly regarded and expertly designed C++ library projects in the world. Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

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Getting Started on Unix Variants

Index

1   Get Boost

The most reliable way to get a copy of Boost is to download a distribution from SourceForge:

  1. Download boost_1_50_0.tar.bz2.

  2. In the directory where you want to put the Boost installation, execute

    tar --bzip2 -xf /path/to/boost_1_50_0.tar.bz2
    

Other Packages

RedHat, Debian, and other distribution packagers supply Boost library packages, however you may need to adapt these instructions if you use third-party packages, because their creators usually choose to break Boost up into several packages, reorganize the directory structure of the Boost distribution, and/or rename the library binaries.1 If you have any trouble, we suggest using an official Boost distribution from SourceForge.

2   The Boost Distribution

This is a sketch of the resulting directory structure:

boost_1_50_0/ .................The “boost root directory”
   index.htm .........A copy of www.boost.org starts here
   boost/ .........................All Boost Header files
    
   libs/ ............Tests, .cpps, docs, etc., by library
     index.html ........Library documentation starts here
     algorithm/
     any/
     array/
                     …more libraries…
   status/ .........................Boost-wide test suite
   tools/ ...........Utilities, e.g. Boost.Build, quickbook, bcp
   more/ ..........................Policy documents, etc.
   doc/ ...............A subset of all Boost library docs

It's important to note the following:

  1. The path to the boost root directory (often /usr/local/boost_1_50_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.

3   Header-Only Libraries

The first thing many people want to know is, “how do I build Boost?” The good news is that often, there's nothing to build.

Nothing to Build?

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:

A few libraries have optional separately-compiled binaries:

4   Build a Simple Program Using Boost

To keep things simple, let's start by using a header-only library. The following program reads a sequence of integers from standard input, uses Boost.Lambda to multiply each number by three, and writes them to standard output:

#include <boost/lambda/lambda.hpp>
#include <iostream>
#include <iterator>
#include <algorithm>

int main()
{
    using namespace boost::lambda;
    typedef std::istream_iterator<int> in;

    std::for_each(
        in(std::cin), in(), std::cout << (_1 * 3) << " " );
}

Copy the text of this program into a file called example.cpp.

Now, in the directory where you saved example.cpp, issue the following command:

c++ -I path/to/boost_1_50_0 example.cpp -o example

To test the result, type:

echo 1 2 3 | ./example

4.1   Errors and Warnings

Don't be alarmed if you see compiler warnings originating in Boost headers. We try to eliminate them, but doing so isn't always practical.3 Errors are another matter. If you're seeing compilation errors at this point in the tutorial, check to be sure you've copied the example program correctly and that you've correctly identified the Boost root directory.

5   Prepare to Use a Boost Library Binary

If you want to use any of the separately-compiled Boost libraries, you'll need to acquire library binaries.

5.1   Easy Build and Install

Issue the following commands in the shell (don't type $; that represents the shell's prompt):

$ cd path/to/boost_1_50_0
$ ./bootstrap.sh --help

Select your configuration options and invoke ./bootstrap.sh again without the --help option. Unless you have write permission in your system's /usr/local/ directory, you'll probably want to at least use

$ ./bootstrap.sh --prefix=path/to/installation/prefix

to install somewhere else. Also, consider using the --show-libraries and --with-libraries=library-name-list options to limit the long wait you'll experience if you build everything. Finally,

$ ./b2 install

will leave Boost binaries in the lib/ subdirectory of your installation prefix. You will also find a copy of the Boost headers in the include/ subdirectory of the installation prefix, so you can henceforth use that directory as an #include path in place of the Boost root directory.

skip to the next step

5.2   Or, Build Custom Binaries

If you're using a compiler other than your system's default, you'll need to use Boost.Build to create binaries.

You'll also use this method if you need a nonstandard build variant (see the Boost.Build documentation for more details).

Boost.CMake

There is also an experimental CMake build for boost, supported and distributed separately. See the Boost.CMake wiki page for more information.

5.2.1   Install Boost.Build

Boost.Build is a text-based system for developing, testing, and installing software. First, you'll need to build and install it. To do this:

  1. Go to the directory tools/build/v2/.
  2. Run bootstrap.sh
  3. Run b2 install --prefix=PREFIX where PREFIX is the directory where you want Boost.Build to be installed
  4. Add PREFIX/bin to your PATH environment variable.

5.2.2   Identify Your Toolset

First, find the toolset corresponding to your compiler in the following table (an up-to-date list is always available in the Boost.Build documentation).

Note

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
acc Hewlett Packard Only very recent versions are known to work well with Boost
borland Borland  
como Comeau Computing Using this toolset may require configuring another toolset to act as its backend
darwin Apple Computer Apple's version of the GCC toolchain with support for Darwin and MacOS X features such as frameworks.
gcc The Gnu Project Includes support for Cygwin and MinGW compilers.
hp_cxx Hewlett Packard Targeted at the Tru64 operating system.
intel Intel  
msvc Microsoft  
sun Sun Only very recent versions are known to work well with Boost.
vacpp IBM 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.

5.2.3   Select a Build Directory

Boost.Build will place all intermediate files it generates while building into the build directory. If your Boost root directory is writable, this step isn't strictly necessary: by default Boost.Build will create a bin.v2/ subdirectory for that purpose in your current working directory.

5.2.4   Invoke b2

Change your current directory to the Boost root directory and invoke b2 as follows:

b2 --build-dir=build-directory toolset=toolset-name   stage

For a complete description of these and other invocation options, please see the Boost.Build documentation.

For example, your session might look like this:

$ cd ~/boost_1_50_0
$ b2 --build-dir=/tmp/build-boost toolset=gcc stage

That will build static and shared non-debug multi-threaded variants of the libraries. To build all variants, pass the additional option, “--build-type=complete”.

Building the special stage target places Boost library binaries in the stage/lib/ subdirectory of the Boost tree. To use a different directory pass the --stagedir=directory option to b2.

Note

b2 is case-sensitive; it is important that all the parts shown in bold type above be entirely lower-case.

For a description of other options you can pass when invoking b2, type:

b2 --help

In particular, to limit the amount of time spent building, you may be interested in:

  • reviewing the list of library names with --show-libraries
  • limiting which libraries get built with the --with-library-name or --without-library-name options
  • choosing a specific build variant by adding release or debug to the command line.

Note

Boost.Build can produce a great deal of output, which can make it easy to miss problems. If you want to make sure everything is went well, you might redirect the output into a file by appending “>build.log 2>&1” to your command line.

5.3   Expected Build Output

During the process of building Boost libraries, you can expect to see some messages printed on the console. These may include

  • Notices about Boost library configuration—for example, the Regex library outputs a message about ICU when built without Unicode support, and the Python library may be skipped without error (but with a notice) if you don't have Python installed.

  • Messages from the build tool that report the number of targets that were built or skipped. Don't be surprised if those numbers don't make any sense to you; there are many targets per library.

  • Build action messages describing what the tool is doing, which look something like:

    toolset-name.c++ long/path/to/file/being/built
    
  • Compiler warnings.

5.4   In Case of Build Errors

The only error messages you see when building Boost—if any—should be related to the IOStreams library's support of zip and bzip2 formats as described here. Install the relevant development packages for libz and libbz2 if you need those features. Other errors when building Boost libraries are cause for concern.

If it seems like the build system can't find your compiler and/or linker, consider setting up a user-config.jam file as described here. If that isn't your problem or the user-config.jam file doesn't work for you, please address questions about configuring Boost for your compiler to the Boost.Build mailing list.

7   Conclusion and Further Resources

This concludes your introduction to Boost and to integrating it with your programs. As you start using Boost in earnest, there are surely a few additional points you'll wish we had covered. One day we may have a “Book 2 in the Getting Started series” that addresses them. Until then, we suggest you pursue the following resources. If you can't find what you need, or there's anything we can do to make this document clearer, please post it to the Boost Users' mailing list.

Onward

Good luck, and have fun!

—the Boost Developers


[1]If developers of Boost packages would like to work with us to make sure these instructions can be used with their packages, we'd be glad to help. Please make your interest known to the Boost developers' list.
[2]That option is a dash followed by a lowercase “L” character, which looks very much like a numeral 1 in some fonts.
[3]Remember that warnings are specific to each compiler implementation. The developer of a given Boost library might not have access to your compiler. Also, some warnings are extremely difficult to eliminate in generic code, to the point where it's not worth the trouble. Finally, some compilers don't have any source code mechanism for suppressing warnings.
[4]This convention distinguishes the static version of a Boost library from the import library for an identically-configured Boost DLL, which would otherwise have the same name.
[5]These libraries were compiled without optimization or inlining, with full debug symbols enabled, and without NDEBUG #defined. Although it's true that sometimes these choices don't affect binary compatibility with other compiled code, you can't count on that with Boost libraries.
[6]This feature of STLPort is deprecated because it's impossible to make it work transparently to the user; we don't recommend it.