387 lines
18 KiB
ReStructuredText
387 lines
18 KiB
ReStructuredText
=================
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libtorrent manual
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=================
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:Author: Arvid Norberg, arvid@rasterbar.com
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.. contents:: Table of contents
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:depth: 2
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:backlinks: none
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downloading and building
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========================
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To acquire the latest version of libtorrent, you'll have to grab it from CVS.
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You'll find instructions on how to do this here__ (see Anonymous CVS access).
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__ http://sourceforge.net/cvs/?group_id=79942
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The build systems supported "out of the box" in libtorrent are boost-build v2
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(BBv2) and autotools (for unix-like systems). If you still can't build after
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following these instructions, you can usually get help in the ``#libtorrent``
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IRC channel on ``irc.freenode.net``.
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building with BBv2
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------------------
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The primary reason to use boost-build is that it will automatically build the
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dependent boost libraries with the correct compiler settings, in order to
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ensure that the build targets are link compatible (see `boost guidelines`__
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for some details on this issue).
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__ http://boost.org/more/separate_compilation.html
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Since BBv2 will build the boost libraries for you, you need the full boost
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source package. Having boost installed via some package system is usually not
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enough (and even if it is enough, the necessary environment variables are
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usually not set by the package installer).
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Step 1: Download boost
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~~~~~~~~~~~~~~~~~~~~~~
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You'll find boost here__.
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__ http://sourceforge.net/project/showfiles.php?group_id=7586&package_id=8041&release_id=376197
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Extract the archive to some directory where you want it. For the sake of this
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guide, let's assume you extract the package to ``c:\boost_1_33_1`` (I'm using
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a windows path in this example since if you're on linux/unix you're more likely
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to use the autotools). You'll need at least version 1.32 of the boost library
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in order to build libtorrent.
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If you use 1.32, you need to download BBv2 separately, so for now, let's
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assume you will use version 1.33.1.
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Step 2: Setup BBv2
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~~~~~~~~~~~~~~~~~~
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First you need to build ``bjam``. You do this by opening a terminal (In
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windows, run ``cmd``). Change directory to
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``c:\boost_1_33_1\tools\build\jam_src``. Then run the script called
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``build.bat`` or ``build.sh`` on a unix system. This will build ``bjam`` and
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place it in a directory starting with ``bin.`` and then have the name of your
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platform. Copy the ``bjam.exe`` (or ``bjam`` on a unix system) to a place
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that's in you shell's ``PATH``. On linux systems a place commonly used may be
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``/usr/local/bin`` or on windows ``c:\windows`` (you can also add directories
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to the search paths by modifying the environment variable called ``PATH``).
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Now you have ``bjam`` installed. ``bjam`` can be considered an interpreter
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that the boost-build system is implemented on. So boost-build uses ``bjam``.
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So, to complete the installation you need to make two more things. You need to
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set the environment variable ``BOOST_BUILD_PATH``. This is the path that tells
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``bjam`` where it can find boost-build, your configuration file and all the
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toolsets (descriptions used by boost-build to know how to use different
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compilers on different platforms). Assuming the boost install path above, set
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it to ``c:\boost_1_33_1\tools\build\v2``.
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To set an environment variable in windows, type for example::
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set BOOST_BUILD_PATH=c:\boost_1_33_1\tools\build\v2
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In a terminal window.
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The last thing to do to complete the setup of BBv2 is to modify your
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``user-config.jam`` file. It is located in ``c:\boost_1_33_1\tools\build\v2``.
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Depending on your platform and which compiler you're using, you should add a
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line for each compiler and compiler version you have installed on your system
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that you want to be able to use with BBv2. For example, if you're using
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Microsoft Visual Studio 7.1 (2003), just add a line::
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using msvc : 7.1 ;
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If you use GCC, add the line::
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using gcc ;
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If you have more than one version of GCC installed, you can add the
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commandline used to invoke g++ after the version number, like this::
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using gcc : 3.3 : g++-3.3 ;
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using gcc : 4.0 : g++-4.0 ;
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Another toolset worth mentioning is the ``darwin`` toolset (For MacOS X).
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From Tiger (10.4) MacOS X comes with both GCC 3.3 and GCC 4.0. Then you can
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use the following toolsets::
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using darwin : 3.3 : g++-3.3 ;
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using darwin : 4.0 : g++-4.0 ;
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Note that the spaces around the semi-colons and colons are important!
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Step 3: Building libtorrent
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~~~~~~~~~~~~~~~~~~~~~~~~~~~
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When building libtorrent, the ``Jamfile`` expects the environment variable
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``BOOST_ROOT`` to be set to the boost installation directory. It uses this to
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find the boost libraries it depends on, so they can be built and their headers
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files found. So, set this to ``c:\boost_1_33_1``.
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Then the only thing left is simply to invoke ``bjam``. If you want to specify
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a specific toolset to use (compiler) you can just add that to the commandline.
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For example::
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bjam msvc-7.1 link=static
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bjam gcc-3.3 link=static
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bjam darwin-4.0 link=static
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To build different versions you can also just add the name of the build
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variant. Some default build variants in BBv2 are ``release``, ``debug``,
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``profile``.
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You can build libtorrent as a dll too, by typing ``link=shared``, or
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``link=static`` to build a static library. ``link=shared`` is the default.
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If you want to explicitly say how to link against the runtime library, you
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can set the ``runtime-link`` feature on the commandline, either to ``shared``
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or ``static``. Most operating systems will only allow linking shared against
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the runtime, but on windows you can do both. Example::
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bjam msvc-7.1 link=static runtime-link=static
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.. warning::
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If you link statically to the runtime library, you cannot build libtorrent
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as a shared library (DLL), since you will get separate heaps in the library
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and in the client application. It will result in crashes.
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The build targets are put in a directory called bin, and under it they are
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sorted in directories depending on the toolset and build variant used.
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To build the examples, just change directory to the examples directory and
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invoke ``bjam`` from there. To build and run the tests, go to the test
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directory and run ``bjam``.
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Note that if you're building on windows using the ``msvc`` toolset, you cannot run it
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from a cygwin terminal, you'll have to run it from a ``cmd`` terminal. The same goes for
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cygwin, if you're building with gcc in cygwin you'll have to run it from a cygwin terminal.
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Also, make sure the paths are correct in the different environments. In cygwin, the paths
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(``BOOST_BUILD_PATH`` and ``BOOST_ROOT``) should be in the typical unix-format (e.g.
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``/cygdrive/c/boost_1_33_1``). In the windows environment, they should have the typical
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windows format (``c:/boost_1_33_1``).
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The ``Jamfile`` will define ``NDEBUG`` when it's building a release build.
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There are two other build variants available in the ``Jamfile``. debug_log
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and release_log, these two variants inherits from the debug and release
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variants respectively, but adds extra logging (``TORRENT_VERBOSE_LOGGING``).
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For more build configuration flags see `Build configurations`_.
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The ``Jamfile`` has the following build variants:
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* ``release`` - release version without any logging
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* ``release_log`` - release version with standard logging
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* ``release_vlog`` - release version with verbose logging (all peer connections are logged)
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* ``debug`` - debug version without any logging
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* ``debug_log`` - debug version with standard logging
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* ``debug_vlog`` - debug version with verbose logging
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The logs created when building vlog or log mode are put in a directory called
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``libtorrent_logs`` in the current working directory.
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When building the example client on windows, you need to build with
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``link=static`` otherwise you may get unresolved external symbols for some
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boost.program-options symbols.
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For more information, see the `Boost build v2 documentation`__.
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__ http://www.boost.org/tools/build/v2/index.html
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building with autotools
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-----------------------
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First of all, you need to install ``automake`` and ``autoconf``. Many
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unix/linux systems comes with these preinstalled.
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Step 1: Generating the build system
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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No build system is present if libtorrent is checked out from CVS - it
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needs to be generated first. If you're building from a released tarball,
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you may skip directly to `Step 2: Running configure`_.
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Execute the following commands, in the given order, to generate
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the build system:
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* aclocal -I m4
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* autoheader
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* libtoolize --copy --force
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* automake --add-missing --copy --gnu
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* autoconf
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Step 2: Running configure
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~~~~~~~~~~~~~~~~~~~~~~~~~
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In your shell, change directory to the libtorrent directory and run
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``./configure``. This will look for libraries and C++ features that libtorrent
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is dependent on. If something is missing or can't be found it will print an
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error telling you what failed.
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The most likely problem you may encounter is that the configure script won't
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find the boost libraries. Make sure you have boost installed on your system.
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The easiest way to install boost is usually to use the preferred package
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system on your platform. Usually libraries and headers are installed in
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standard directories where the compiler will find them, but sometimes that
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may not be the case. For example when installing boost on darwin using
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darwinports (the package system based on BSD ports) all libraries are
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installed to ``/opt/local/lib`` and headers are installed to
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``/opt/local/include``. By default the compiler will not look in these
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directories. You have to set the enviornment variables ``LDFLAGS`` and
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``CXXFLAGS`` in order to make the compiler find those libs. In this example
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you'd set them like this::
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export LDFLAGS=-L/opt/local/lib
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export CXXFLAGS=-I/opt/local/include
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It was observed on FreeBSD (release 6.0) that one needs to add '-lpthread' to
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LDFLAGS, as Boost::Thread detection will fail without it, even if
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Boost::Thread is installed.
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If you need to set these variables, it may be a good idea to add those lines
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to your ``~/.profile`` or ``~/.tcshrc`` depending on your shell.
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You know that the boost libraries were found if you see the following output
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from the configure script::
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checking whether the Boost::DateTime library is available... yes
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checking for main in -lboost_date_time... yes
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checking whether the Boost::Filesystem library is available... yes
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checking for main in -lboost_filesystem... yes
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checking whether the Boost::Thread library is available... yes
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checking for main in -lboost_thread... yes
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Another possible source of problems may be if the path to your libtorrent
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directory contains spaces. Make sure you either rename the directories with
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spaces in their names to remove the spaces or move the libtorrent directory.
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Creating a debug build
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~~~~~~~~~~~~~~~~~~~~~~
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To tell configure to build a debug version (with debug info, asserts
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and invariant checks enabled), you have to run the configure script
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with the following option::
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./configure --enable-debug=yes
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Creating a release build
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~~~~~~~~~~~~~~~~~~~~~~~~
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To tell the configure to build a release version (without debug info,
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asserts and invariant checks), you have to run the configure script
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with the following option::
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./configure --enable-debug=no
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The above option make use of -DNDEBUG, which is used throughout libtorrent.
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Step 3: Building libtorrent
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~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Once the configure script is run successfully, you just type ``make`` and
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libtorrent, the examples and the tests will be built.
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When libtorrent is built it may be a good idea to run the tests, you do this
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by running ``make check``.
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If you want to build a release version (without debug info, asserts and
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invariant checks), you have to rerun the configure script and rebuild, like this::
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./configure --disable-debug
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make clean
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make
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building with other build systems
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---------------------------------
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If you're making your own project file, note that there are two versions of
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the file abstraction. There's one ``file_win.cpp`` which relies on windows
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file API that supports files larger than 2 Gigabytes. This does not work in
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vc6 for some reason, possibly because it may require windows NT and above.
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The other file, ``file.cpp`` is the default implementation that simply relies
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on the standard low level io routines (``read()``, ``write()``, ``open()``
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etc.), this implementation doesn't do anything special to support unicode
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filenames, so if your target is Windows 2000 and up, you may want to use
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``file_win.cpp`` which supports unicode filenames.
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If you're building in MS Visual Studio, you may have to set the compiler
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options "force conformance in for loop scope", "treat wchar_t as built-in
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type" and "Enable Run-Time Type Info" to Yes. For a detailed description
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on how to build libtorrent with VS 2005, see `this document`_.
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.. _`this document`: vs2005_build_notes.html
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build configurations
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--------------------
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By default libtorrent is built In debug mode, and will have pretty expensive
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invariant checks and asserts built into it. If you want to disable such checks
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(you want to do that in a release build) you can see the table below for which
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defines you can use to control the build.
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+--------------------------------+-------------------------------------------------+
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| macro | description |
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+================================+=================================================+
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| ``NDEBUG`` | If you define this macro, all asserts, |
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| | invariant checks and general debug code will be |
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| | removed. This option takes precedence over |
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| | other debug settings. |
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+--------------------------------+-------------------------------------------------+
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| ``TORRENT_LOGGING`` | This macro will enable logging of the session |
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| | events, such as tracker announces and incoming |
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| | connections (as well as blocked connections). |
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+--------------------------------+-------------------------------------------------+
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| ``TORRENT_VERBOSE_LOGGING`` | If you define this macro, every peer connection |
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| | will log its traffic to a log file as well as |
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| | the session log. |
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+--------------------------------+-------------------------------------------------+
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| ``TORRENT_STORAGE_DEBUG`` | This will enable extra expensive invariant |
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| | checks in the storage, including logging of |
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| | piece sorting. |
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+--------------------------------+-------------------------------------------------+
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| ``UNICODE`` | If building on windows this will make sure the |
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| | UTF-8 strings in pathnames are converted into |
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| | UTF-16 before they are passed to the file |
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| | operations. |
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+--------------------------------+-------------------------------------------------+
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| ``LITTLE_ENDIAN`` | This will use the little endian version of the |
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| | sha-1 code. If defined on a big-endian system |
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| | the sha-1 hashes will be incorrect and fail. |
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| | If it is not defined and ``__BIG_ENDIAN__`` |
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| | isn't defined either (it is defined by Apple's |
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| | GCC) both little-endian and big-endian versions |
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| | will be built and the correct code will be |
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| | chosen at run-time. |
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+--------------------------------+-------------------------------------------------+
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| ``TORRENT_LINKING_SHARED`` | If this is defined when including the |
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| | libtorrent headers, the classes and functions |
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| | will be tagged with ``__declspec(dllimport)`` |
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| | on msvc and default visibility on GCC 4 and |
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| | later. Set this in your project if you're |
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| | linking against libtorrent as a shared library. |
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| | (This is set by the Jamfile when |
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| | ``link=shared`` is set). |
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+--------------------------------+-------------------------------------------------+
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| ``TORRENT_BUILDING_SHARED`` | If this is defined, the functions and classes |
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| | in libtorrent are marked with |
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| | ``__declspec(dllexport)`` on msvc, or with |
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| | default visibility on GCC 4 and later. This |
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| | should be defined when building libtorrent as |
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| | a shared library. (This is set by the Jamfile |
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| | when ``link=shared`` is set). |
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+--------------------------------+-------------------------------------------------+
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| ``TORRENT_DISABLE_DHT`` | If this is defined, the support for trackerless |
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|<7C> | torrents will be disabled. |
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+--------------------------------+-------------------------------------------------+
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If you experience that libtorrent uses unreasonable amounts of cpu, it will
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definitely help to define ``NDEBUG``, since it will remove the invariant checks
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within the library.
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|