| Author: | Arvid Norberg, arvid@libtorrent.org |
|---|---|
| Version: | 1.2.0 |
Table of contents
To download the latest version of libtorrent, clone the github repo.
The build systems supported "out of the box" in libtorrent are boost-build v2
(BBv2) and autotools (for unix-like systems). If you still can't build after
following these instructions, you can usually get help in the #libtorrent
IRC channel on irc.freenode.net.
Warning
A common mistake when building and linking against libtorrent is to build with one set of configuration options (#defines) and link against it using a different set of configuration options. Since libtorrent has some code in header files, that code will not be compatible with the built library if they see different configurations.
Always make sure that the same TORRENT_* macros are defined when you link against libtorrent as when you build it.
Boost-build supports propagating configuration options to dependencies. When building using the makefiles, this is handled by setting the configuration options in the pkg-config file. Always use pkg-config when linking against libtorrent.
To build libtorrent from git you need to clone the libtorrent repo from github. If you downloaded a release tarball, you can skip this section.
git clone https://github.com/arvidn/libtorrent.git
The primary reason to use boost-build is that it will automatically build the dependent boost libraries with the correct compiler settings, in order to ensure that the build targets are link compatible (see boost guidelines for some details on this issue).
Since BBv2 will build the boost libraries for you, you need the full boost source package. Having boost installed via some package system is usually not enough (and even if it is enough, the necessary environment variables are usually not set by the package installer).
If you want to build against an installed copy of boost, you can skip directly to step 3 (assuming you also have boost build installed).
You'll find boost here.
Extract the archive to some directory where you want it. For the sake of this
guide, let's assume you extract the package to c:\boost_1_64_0 (I'm using
a windows path in this example since if you're on linux/unix you're more likely
to use the autotools). You'll need at least version 1.49 of the boost library
in order to build libtorrent.
First you need to build bjam. You do this by opening a terminal (In
windows, run cmd). Change directory to
c:\boost_1_64_0\tools\jam\src. Then run the script called
build.bat or build.sh on a unix system. This will build bjam and
place it in a directory starting with bin. and then have the name of your
platform. Copy the bjam.exe (or bjam on a unix system) to a place
that's in you shell's PATH. On linux systems a place commonly used may be
/usr/local/bin or on windows c:\windows (you can also add directories
to the search paths by modifying the environment variable called PATH).
Now you have bjam installed. bjam can be considered an interpreter
that the boost-build system is implemented on. So boost-build uses bjam.
So, to complete the installation you need to make two more things. You need to
set the environment variable BOOST_BUILD_PATH. This is the path that tells
bjam where it can find boost-build, your configuration file and all the
toolsets (descriptions used by boost-build to know how to use different
compilers on different platforms). Assuming the boost install path above, set
it to c:\boost_1_64_0\tools\build\v2.
To set an environment variable in windows, type for example:
set BOOST_BUILD_PATH=c:\boost_1_64_0\tools\build\v2
In a terminal window.
The last thing to do to complete the setup of BBv2 is to modify your
user-config.jam file. It is located in c:\boost_1_64_0\tools\build\v2.
Depending on your platform and which compiler you're using, you should add a
line for each compiler and compiler version you have installed on your system
that you want to be able to use with BBv2. For example, if you're using
Microsoft Visual Studio 12 (2013), just add a line:
using msvc : 12.0 ;
If you use GCC, add the line:
using gcc ;
If you have more than one version of GCC installed, you can add the commandline used to invoke g++ after the version number, like this:
using gcc : 3.3 : g++-3.3 ; using gcc : 4.0 : g++-4.0 ;
Another toolset worth mentioning is the darwin toolset (For MacOS X).
From Tiger (10.4) MacOS X comes with both GCC 3.3 and GCC 4.0. Then you can
use the following toolsets:
using darwin : 3.3 : g++-3.3 ; using darwin : 4.0 : g++-4.0 ;
Note that the spaces around the semi-colons and colons are important!
Also see the official installation instructions.
When building libtorrent, the Jamfile expects the environment variable
BOOST_ROOT to be set to the boost installation directory. It uses this to
find the boost libraries it depends on, so they can be built and their headers
files found. So, set this to c:\boost_1_64_0. You only need this if you're
building against a source distribution of boost.
Then the only thing left is simply to invoke bjam. If you want to specify
a specific toolset to use (compiler) you can just add that to the commandline.
For example:
bjam msvc-7.1 bjam gcc-3.3 bjam darwin-4.0
Note
If the environment variable BOOST_ROOT is not set, the jamfile will
attempt to link against "installed" boost libraries. i.e. assume the headers
and libraries are available in default search paths.
To build different versions you can also just add the name of the build
variant. Some default build variants in BBv2 are release, debug,
profile.
You can build libtorrent as a dll too, by typing link=shared, or
link=static to build a static library.
If you want to explicitly say how to link against the runtime library, you
can set the runtime-link feature on the commandline, either to shared
or static. Most operating systems will only allow linking shared against
the runtime, but on windows you can do both. Example:
bjam msvc-7.1 link=static runtime-link=static
Note
When building on windows, the path boost-build puts targets in may be too long. If you get an error message like: "The input line is long", try to pass --abbreviate-paths on the bjam command line.
Warning
If you link statically to the runtime library, you cannot build libtorrent as a shared library (DLL), since you will get separate heaps in the library and in the client application. It will result in crashes and possibly link errors.
Note
With boost-build V2 (Milestone 11), the darwin toolset uses the -s linker
option to strip debug symbols. This option is buggy in Apple's GCC, and
will make the executable crash on startup. On Mac OS X, instead build
your release executables with the debug-symbols=on option, and
later strip your executable with strip.
Note
Some linux systems requires linking against librt in order to access
the POSIX clock functions. If you get an error complaining about a missing
symbol clock_gettime, you have to give need-librt=yes on the
bjam command line. This will make libtorrent link against librt.
Note
When building on Solaris, you might have to specify stdlib=sun-stlport
on the bjam command line.
The build targets are put in a directory called bin, and under it they are sorted in directories depending on the toolset and build variant used.
To build the examples, just change directory to the examples directory and
invoke bjam from there. To build and run the tests, go to the test
directory and run bjam.
Note that if you're building on windows using the msvc toolset, you cannot run it
from a cygwin terminal, you'll have to run it from a cmd terminal. The same goes for
cygwin, if you're building with gcc in cygwin you'll have to run it from a cygwin terminal.
Also, make sure the paths are correct in the different environments. In cygwin, the paths
(BOOST_BUILD_PATH and BOOST_ROOT) should be in the typical unix-format (e.g.
/cygdrive/c/boost_1_64_0). In the windows environment, they should have the typical
windows format (c:/boost_1_64_0).
Note
In Jamfiles, spaces are separators. It's typically easiest to avoid spaces in path names. If you want spaces in your paths, make sure to quote them with double quotes (").
The Jamfile will define NDEBUG when it's building a release build.
For more build configuration flags see Build configurations.
When enabling linking against openssl (by setting the crypto feature to
openssl) the Jamfile will look in some default directory for the openssl
headers and libraries. On macOS, it will look for the homebrew openssl package.
On windows it will look in c:\openssl and mingw in c:\OpenSSL-Win32.
To customize the library path and include path for openssl, set the features
openssl-lib and openssl-include respectively.
Build features:
| boost build feature | values |
|---|---|
boost-link |
|
openssl-lib |
can be used to specify the directory where libssl and libcrypto are installed (or the windows counterparts). |
openssl-include |
can be used to specify the include directory where the openssl headers are installed. |
logging |
|
dht |
|
asserts |
|
encryption |
|
mutable-torrents |
|
crypto |
|
openssl-version |
This can be used on windows to link against the special OpenSSL library names used on windows prior to OpenSSL 1.1.
|
allocator |
|
link |
|
runtime-link |
|
variant |
|
invariant-checks |
This setting only affects debug builds (where
|
debug-symbols |
|
deprecated-functions |
|
iconv |
|
i2p |
|
profile-calls |
|
The variant feature is implicit, which means you don't need to specify
the name of the feature, just the value.
The logs created when building vlog or log mode are put in a directory called
libtorrent_logs in the current working directory.
When building the example client on windows, you need to build with
link=static otherwise you may get unresolved external symbols for some
boost.program-options symbols.
For more information, see the Boost build v2 documentation, or more specifically the section on builtin features.
First of all, you need to install automake and autoconf. Many
unix/linux systems comes with these preinstalled.
The prerequisites for building libtorrent are boost.system, boost.chrono and boost.random. Those are the compiled boost libraries needed. The headers-only libraries needed include (but is not necessarily limited to) boost.bind, boost.ref, boost.multi_index, boost.optional, boost.lexical_cast, boost.integer, boost.iterator, boost.tuple, boost.array, boost.function, boost.smart_ptr, boost.preprocessor, boost.static_assert.
If you want to build the client_test example, you'll also need boost.regex
and boost.program_options.
No build system is present if libtorrent is checked out from CVS - it needs to be generated first. If you're building from a released tarball, you may skip directly to Step 2: Running configure.
Execute the following command to generate the build system:
./autotool.sh
In your shell, change directory to the libtorrent directory and run
./configure. This will look for libraries and C++ features that libtorrent
is dependent on. If something is missing or can't be found it will print an
error telling you what failed.
The most likely problem you may encounter is that the configure script won't
find the boost libraries. Make sure you have boost installed on your system.
The easiest way to install boost is usually to use the preferred package
system on your platform. Usually libraries and headers are installed in
standard directories where the compiler will find them, but sometimes that
may not be the case. For example when installing boost on darwin using
darwinports (the package system based on BSD ports) all libraries are
installed to /opt/local/lib and headers are installed to
/opt/local/include. By default the compiler will not look in these
directories. You have to set the enviornment variables LDFLAGS and
CXXFLAGS in order to make the compiler find those libs. In this example
you'd set them like this:
export LDFLAGS=-L/opt/local/lib export CXXFLAGS=-I/opt/local/include
It was observed on FreeBSD (release 6.0) that one needs to add '-lpthread' to LDFLAGS, as Boost::Thread detection will fail without it, even if Boost::Thread is installed.
If you need to set these variables, it may be a good idea to add those lines
to your ~/.profile or ~/.tcshrc depending on your shell.
If the boost libraries are named with a suffix on your platform, you may use
the --with-boost-thread= option to specify the suffix used for the thread
library in this case. For more information about these options, run:
./configure --help
On gentoo the boost libraries that are built with multi-threading support have
the suffix mt.
You know that the boost libraries were found if you see the following output from the configure script:
Checking for boost libraries: checking for boostlib >= 1.53... yes checking whether the Boost::System library is available... yes checking for exit in -lboost_system... yes checking whether the Boost::Chrono library is available... yes checking for exit in -lboost_chrono-mt... yes checking whether the Boost::Random library is available... yes checking for exit in -lboost_random-mt... yes
Another possible source of problems may be if the path to your libtorrent directory contains spaces. Make sure you either rename the directories with spaces in their names to remove the spaces or move the libtorrent directory.
To tell configure to build a debug version (with debug info, asserts and invariant checks enabled), you have to run the configure script with the following option:
./configure --enable-debug=yes
To tell the configure to build a release version (without debug info, asserts and invariant checks), you have to run the configure script with the following option:
./configure --enable-debug=no
The above option make use of -DNDEBUG, which is used throughout libtorrent.
Once the configure script is run successfully, you just type make and
libtorrent, the examples and the tests will be built.
When libtorrent is built it may be a good idea to run the tests, you do this
by running make check.
If you want to build a release version (without debug info, asserts and invariant checks), you have to rerun the configure script and rebuild, like this:
./configure --disable-debug make clean make
If you're building in MS Visual Studio, you may have to set the compiler options "force conformance in for loop scope", "treat wchar_t as built-in type" and "Enable Run-Time Type Info" to Yes.
By default libtorrent is built In debug mode, and will have pretty expensive invariant checks and asserts built into it. If you want to disable such checks (you want to do that in a release build) you can see the table below for which defines you can use to control the build.
| macro | description |
|---|---|
NDEBUG |
If you define this macro, all asserts, invariant checks and general debug code will be removed. Since there is quite a lot of code in in header files in libtorrent, it may be important to define the symbol consistently across compilation units, including the clients files. Potential problems is different compilation units having different views of structs and class layouts and sizes. |
TORRENT_DISABLE_LOGGING |
This macro will disable support for logging alerts, like log_alert, torrent_log_alert and peer_log_alert. With this build flag, you cannot enable those alerts. |
TORRENT_DISABLE_MUTABLE_TORRENTS |
Disables mutable torrent support (BEP 38) |
TORRENT_LINKING_SHARED |
If this is defined when including the
libtorrent headers, the classes and functions
will be tagged with __declspec(dllimport)
on msvc and default visibility on GCC 4 and
later. Set this in your project if you're
linking against libtorrent as a shared library.
(This is set by the Jamfile when
link=shared is set). |
TORRENT_BUILDING_SHARED |
If this is defined, the functions and classes
in libtorrent are marked with
__declspec(dllexport) on msvc, or with
default visibility on GCC 4 and later. This
should be defined when building libtorrent as
a shared library. (This is set by the Jamfile
when link=shared is set). |
TORRENT_DISABLE_DHT |
If this is defined, the support for trackerless torrents will be disabled. |
TORRENT_DISABLE_ENCRYPTION |
This will disable any encryption support and
the dependencies of a crypto library.
Encryption support is the peer connection
encrypted supported by clients such as
uTorrent, Azureus and KTorrent.
If this is not defined, either
TORRENT_USE_LIBCRYPTO or
TORRENT_USE_LIBGCRYPT must be defined. |
TORRENT_DISABLE_EXTENSIONS |
When defined, libtorrent plugin support is disabled along with support for the extension handskake (BEP 10). |
TORRENT_USE_INVARIANT_CHECKS |
If defined to non-zero, this will enable internal invariant checks in libtorrent. The invariant checks can sometimes be quite expensive, they typically don't scale very well. |
TORRENT_EXPENSIVE_INVARIANT_CHECKS |
This will enable extra expensive invariant checks. Useful for finding particular bugs or for running before releases. |
TORRENT_NO_DEPRECATE |
This will exclude all deprecated functions from the header files and cpp files. |
TORRENT_PRODUCTION_ASSERTS |
Define to either 0 or 1. Enables assert logging in release builds. |
TORRENT_USE_ASSERTS |
Define as 0 to disable asserts unconditionally. |
TORRENT_USE_SYSTEM_ASSERTS |
Uses the libc assert macro rather then the custom one. |
If you experience that libtorrent uses unreasonable amounts of cpu, it will
definitely help to define NDEBUG, since it will remove the invariant checks
within the library.
To build openssl for windows with Visual Studio 7.1 (2003) execute the following commands in a command shell:
perl Configure VC-WIN32 --prefix="c:/openssl call ms\do_nasm call "C:\Program Files\Microsoft Visual Studio .NET 2003\vc7\bin\vcvars32.bat" nmake -f ms\nt.mak copy inc32\openssl "C:\Program Files\Microsoft Visual Studio .NET 2003\vc7\include\" copy out32\libeay32.lib "C:\Program Files\Microsoft Visual Studio .NET 2003\vc7\lib" copy out32\ssleay32.lib "C:\Program Files\Microsoft Visual Studio .NET 2003\vc7\lib"
This will also install the headers and library files in the visual studio directories to be picked up by libtorrent.