Chapter 3
Installation

Eric Berberich, Joachim Reichel, and Fernando Cacciola

Table of Contents

3.1   Introduction

This document describes how to install Cgal on Windows, Unix-like systems, and MacOS X.

Ideally, setting up Cgal amounts to:

  cd  CGAL-4.1                                # go to Cgal directory
  cmake .                                     # configure Cgal
  make                                        # build the Cgal libraries

Compiling an example shipped with Cgal is similar simple:

  cd examples/Straight_skeleton_2             # go to an example directory
  cmake -DCGAL_DIR=$HOME/CGAL-4.1 .           # configure the examples
  make                                        # build the examples 

Compiling an own non-shipped program is also close:

cd /path/to/program 
cgal_create_CMakeLists -s executable 
cmake -DCGAL_DIR=$HOME/CGAL-4.1 . 
make

where the second line creates a CMakeLists.txt file (check its options in Section 3.15.1.1 for various details).

In a less ideal world, you probably have to install CMake, a makefile generator, and third party libraries. That is what this manual is about.

3.2   Prerequisites

Installing Cgal requires a few components to be installed ahead: a supported compiler (see Section 3.5, CMake, Boost, and at least Gmp, and Mpfr; see Section 3.8 for more details on essential third party software.

3.3   OS-shipped Cgal

Some operating systems with package managers offer Cgal and its essential third party software through the manager, for instance, Mac OS X, or some Linux distribution (e.g. Debian).

3.3.1   Cgal on MAC OS X

For instance, use macports in the following way:

 sudo port install cgal

or if Qt4 demos are desired

 sudo port install cgal +qt4 +universal +demos

The setup is similar for homebrew.

3.3.2   Cgal on Linux

For instance in debian/Ubuntu, use apt-get in the following way:

 sudo apt-get install libcgal-dev

To get the demos use

 sudo apt-get install libcgal-demo

Check the Cgal-FAQ for source repository of newest releases.

On other distributions, please consult your package manager documentation.

3.4   Downloading Cgal

You can obtain the Cgal library from http://www.cgal.org/download.html and install it yourself.

After you have downloaded the file CGAL-4.1.tar.gz containing the Cgal sources, you have to unpack it. Under a Unix-like shell, use the command:

      tar xzf CGAL-4.1.tar.gz

When you are on Windows you may download and run CGAL-4.1-Setup.exe. It is a self extracting executable that installs the Cgal source, and that allows you to select and download some precompiled third party libraries.

In both cases the directory CGAL-4.1 will be created. This directory contains the following subdirectories:

The directories include/CGAL/CORE and src/CGALCore contain a distribution of the Core library¹ version 1.7 for dealing with algebraic numbers. Core is not part of Cgal and has its own license.

The directory include/CGAL/OpenNL contains a distribution of the Open Numerical Library which provides solvers for sparse linear systems, especially designed for the Computer Graphics community. OpenNL is not part of Cgal and has its own license.

The only documentation shipped with Cgal sources is the present installation manual. The Cgal manual must be downloaded separately from http://www.cgal.org/download.html.

3.5   Supported Compilers

In order to build the Cgal libraries, you need a C++ compiler. Cgal 4.1 is supported for the following compilers/operating systems:

3.6   Configuring Cgal with CMake

In order to configure, build, and install the Cgal libraries, examples and demos, you need CMake, a cross-platform ``makefile generator''. If CMake is not installed already you can obtain it from http://www.cmake.org/. CMake version 2.6.2 or higher is required. On Windows, CMake version 2.8.6 or higher is required, for a proper support of DLL's generation. This manual explains only those features of CMake which are needed in order to build Cgal. Please refer to the CMake documentation at http://www.cmake.org/ for further details.

Before building Cgal you have to choose the compiler/linker, set compiler and linker flags, specify which third-party libraries you want to use and where they can be found, and which Cgal libraries you want to build. Gathering all this information is called configuration. The end of the process is marked by the generation of a makefile or a Visual C++ solution and project file that you can use to build Cgal.

3.6.1   Configuring Cgal with the CMake Gui

The simplest way to start the configuration is to run the graphical user interface of CMake. We recommend to use cmake-gui. It is available on many platforms as of CMake version 2.6. You must pass as argument the root directory of Cgal. For example:

  cd  CGAL-4.1
  cmake-gui . # Notice the dot to indicate the current directory.

After cmake-gui opens, press 'Configure'. A dialog will pop up and you will have to choose what shall gets generated. After you have made your choice and pressed 'Finish', you will see the output of configuration tests in the lower portion of the application. When these tests are done, you will see many red entries in the upper portion of the application. Just ignore them and press 'Configure'. By now CMake should have found many libraries and have initialized variables. If you still find red entries, you have to provide the necessary information. This typically happens if you have installed software at non-standard locations. Providing information and pressing 'Configure' goes on until all entries are grayed. You are now ready to press 'Generate'. Once this is done, you can quit cmake-gui.

3.6.2   Configuring Cgal with the cmake command-line tool

Alternatively, you can run the command-line tool called cmake. You pass as argument the root directory of Cgal. For example:

  cd  CGAL-4.1
  cmake . # Notice the dot to indicate the current directory.

The very first thing CMake does is to detect the compiler to use. This detection is performed by a special CMake module called a generator. A CMake generator understands the build requirements for a particular compiler/linker and generates the necessary files for that. For example, the UNIX Makefiles generator understands the GNU chain of tools (g++, ld etc.) and produces makefiles, which can be used to build a target by a simple call to make. Likewise, the Visual Studio 2010 generator produces solution and project files and can be manually launched in the VS IDE to build the target.

Each platform has a default generator, so you only need to select one when the default is not what you want. For example, under Windows, it is possible to generate NMakefiles instead of Visual Studio project files in order to build the library with nmake. Running cmake with no parameters in a command-line prints the list of available generators supported by your platform and CMake version. If the generator you need is not listed there, you can try a newer CMake version, as generators are hardcoded into CMake, and additional generators are added with each release.

Since the choice of the generator determines the type of build files to generate, in some cases you choose a particular generator as a mean to choose a specific compiler (because they use different build files). For example, the following generates solution files for use in Visual C++ 11.0 on a 64bit machine:

  cd CGAL-4.1
  cmake -G"Visual Studio 11 Win64" . 

In other cases, however, the generator doesn't directly identify a specific compiler but a chain of tools. For example, the UNIX Makefiles generator produces makefiles that call some auto-detected command-line compiler, like g++. If you need the makefiles to use a different compiler, you need to specify the desired compiler in the call to CMake, as in this example:

  cd CGAL-4.1
  cmake -DCMAKE_CXX_COMPILER:FILEPATH=g++-4.7 . 

CMake maintains configuration parameters in so-called cmake variables, like the CMAKE_CXX_COMPILER in the example above. These variables are not environment variables but CMake variables. Some of the CMake variables represent user choices, such as WITH_examples or CMAKE_BUILD_TYPE=Release, while others indicate the details of a third-party library, such as Boost_INCLUDE_DIR or the compiler flags to use, such as CMAKE_CXX_FLAGS.

The command line tool cmake accepts CMake variables as arguments of the form -D<VAR>:<TYPE>=<VALUE>, as in the example above, but this is only useful if you already know which variables need to be explicitly defined.

The configuration process not only determines the location of the required dependencies, it also dynamically generates a compiler_config.h file, which encodes the properties of your system and a special file named CGALConfig.cmake, which is used to build programs using Cgal. The purpose of this file is explained below.

3.7   Cgal Libraries

Cgal is split into five libraries. During configuration, you can select the libraries that you would like to build by setting a CMake variable of the form WITH_<library>. By default all are switched ON. All activated libraries are build after configuration; see 3.11

We next list the libraries and essential 3rd party software (see 3.8) for each library:

3.7.1   Debug vs. Release

The CMake variable CMAKE_BUILD_TYPE indicates how to build the libraries. It accepts the values Release or Debug. The default is Release and should be kept, unless you want to debug your program.

This is not an issue for solution/project files, as there the user selects the build type from within the IDE.

3.7.2   Static vs. Shared Libraries

Shared libraries, also called dynamic-link libraries, are built by default (.dll on Windows, .so on Linux, .dylib on MacOS). You can choose to produce static libraries instead by setting the CMake variable BUILD_SHARED_LIBS to FALSE. If you use cmake-gui, a tick box for that variable is available to set it.

These setting affect the variants of third-party libraries (see next section) selected whenever the choice is available.

3.8   Essential Third Party Libraries

The focus of Cgal is on geometry, and we rely on other highly specialized libraries and software for non-geometric issues, for instance, for numeric solvers, or visualization. We first list software that is essential to build (all) libraries of Cgal, that is, this software must be found during the configuration of Cgal for an actived library of Cgal (i.e. WITH_<library>=ON); see 3.16.4 to specify the location of 3rd party software.

The libraries STL (shipped with any compiler) and Boost are essential to all components (i.e. libCGAL, libCGAL_Core, libCGAL_imageIO, libCGAL_Qt3 and libCGAL_Qt4).

3.8.1   Standard Template Library (STL)

Cgal heavily uses the STL, and in particular adopted many of its design ideas. You can find online documentation for the STL at various web sites, for instance, http://www.sgi.com/tech/stl/, http://www.cplusplus.com/reference/, or http://msdn.microsoft.com/en-us/library/1fe2x6kt(VS.100).aspx.

The STL comes with the compiler, so there is nothing to install.

3.8.2   Boost

The Boost libraries are a set of portable C++ source libraries. Most of Boost libraries are header-only, but a few of them need to be compiled or installed as binaries.

Cgal requires the Boost libraries. In particular the header files and the threading library (Boost.Thread and Boost.System binaries). Version 1.39 (or higher) are needed.

On Windows, as auto-linking is used, you also need the binaries of Boost.Serialization and Boost.DateTime, but the dependency is artificial and used only at link-time: the CGAL libraries do not depend on the DLL's of those two libraries.

In Cgal some demos and examples depend on Boost.Program_options.

In case the Boost libraries are not installed on your system already, you can obtain them from http://www.boost.org/. For Windows you can download an installer from http://www.boostpro.com/download/. Since Boost.Thread is required, make sure to either install the precompiled libraries for your compiler or build libboost-thread and libboost-system.

As on Windows there is no canonical directory for where to find Boost, we recommend that you define the environment variable BOOST_ROOT and set it to where you have installed Boost, e.g., C:\boost\boost_1_41_0.

3.8.3   Gmp and Mpfr

The components libCGAL, libCGAL_Core, libCGAL_Qt3 and libCGAL_Qt4 require Gmp and Mpfr which are libraries for multi precision integers and rational numbers, and for multi precision floating point numbers.

Cgal combines floating point arithmetic with exact arithmetic, in order to be efficient and reliable. Cgal has a built-in number type for that, but Gmp and Mpfr provide a faster solution, and we recommend to use them.

Having Gmp version 4.2 or higher and Mpfr version 2.2.1 or higher installed is recommended. These libraries can be obtained from http://gmplib.org/ and http://www.mpfr.org/, respectively.

As Visual C++ is not properly supported by the Gmp and Mpfr projects, we provide precompiled versions of Gmp and Mpfr, which can be downloaded with the installer CGAL-4.1-Setup.exe.

3.8.4   zlib

zlib is a data compression library, and is essential for the component libCGAL_ImageIO.

In Cgal this library is used in the examples of the Surface Mesh Generation package.

If it is not already on your system, for instance, on Windows, you can download it from http://www.zlib.net/.

3.8.5   OpenGL

OpenGL (Open Graphics Library) provides an API for applications that produce 2D and 3D computer graphics.

In Cgal the library is essential for the components libCGAL_Qt3 and libCGAL_Qt4, as well as libCGAL_ImageIO and for various demos.

Typically, OpenGL is preinstalled on systems; if not, it can be downloaded from http://www.opengl.org/.

3.8.6   Qt3 and Qt4

Qt is a cross-platform application and UI framework.

The component libCGAL_Qt3 requires Qt3 installed on your system, while the component libCGAL_Qt4 requires Qt4 installed on your system. In case Qt is not yet installed on your system, you can download it from http://qt.nokia.com/.

Older demos of Cgaluse libCGAL_Qt3 and Qt3, while newer and newly developed demos require libCGAL_Qt4 and Qt4.

Having Qt4 version 4.3.0 or higher is recommended.

3.9   Cgal Examples and Demos

Cgal is distributed with a large collection of examples and demos. By default, these are not configured along with the Cgal libraries, unless you set the variables WITH_examples=ON and/or WITH_demos=ON.

Nevertheless, even when configured with Cgal, they are not automatically built along with the libraries. You must build the examples or demos targets (or IDE projects) explicitly.

If you do not plan to compile any demos, you might skip some of the essential libraries (as Qt or OpenGL), as the corresponding Cgal-libraries are not linked. But for your own demos you might need these Cgal-libraries.

3.10   Optional Third Party Libraries

Optional 3rd party software can be used by Cgal for various reasons: Usually certain optional libraries are required to build examples and demos shipped with Cgal or to build your own project using Cgal. Another reason is to speed up basic tasks. In order to support these goals, all optional libraries can be prepared to be used with Cgal while configuring Cgal, just in the same way as essential libraries are configured. Whenever building an example or a demo (or your own executable), these preconfigured libraries are available when using Cgal.

3.10.1   Leda

Leda is a library of efficient data structures and algorithms. Like Core, Leda offers a real number data type.

In Cgal this library is optional, and its number types can be used as an alternative to Gmp, Mpfr, and Core.

Free and commercial editions of Leda are available from http://www.algorithmic-solutions.com/leda/index.html.

3.10.2   Mpfi

Mpfi provide arbitrary precision interval arithmetic with intervals represented using Mpfr reliable floating-point numbers. It is based on the Gmp library and on the Mpfr library. In the setting of Cgal it is mainly used in sync with Rs. The library is optional and needed in certain algebraic kernels.

Mpfi can be downloaded from http://mpfi.gforge.inria.fr/. Version 1.4 or higher is recommended.

3.10.3   Rs and Rs3

Rs (Real Solutions) is devoted to the study of the real roots of polynomial systems with a finite number of complex roots (including univariate polynomials).

In Cgal, Rs is used by one model of the Algebraic Kernel.

Rs is freely distributable for non-commercial use. You can download it from http://vegas.loria.fr/rs/. The library Rs needs Mpfi, which can be downloaded from http://mpfi.gforge.inria.fr/. Version 1.4 or higher is recommended.

The successor of Rs is called Rs3. It less restrictive when it comes to licencing and also contains improved and more efficient interfaces. Mainly parts in Cgal's algebraic kernel require Rs3.

3.10.4   Ntl

Ntl provides data structures and algorithms for signed, arbitrary length integers, and for vectors, matrices, and polynomials over the integers and over finite fields. The optional library Ntl is used by Cgal to speed up operations of the Polynomial package, such as GCDs. It is recommended to install Ntl with support from Gmp.

Ntl can be downloaded from http://www.shoup.net/ntl/. Version 5.1 or higher is recommended.

3.10.5   Eigen

In Cgal, Eigen provides sparse linear solvers in the Surface Reconstruction from Point Sets and the Planar Parameterization of Triangulated Surface Meshes packages.

In addition, Eigen also provides singular value decomposition for the Estimation of Local Differential Properties and the Approximation of Ridges and Umbilics packages.

The Eigen web site is http://eigen.tuxfamily.org.

3.10.6   libQGLViewer

libQGLViewer is a 3D widget based on Qt 4's QGLWidget.

In Cgal some 3D demos are based on libQGLViewer.

It can be downloaded from http://www.libqglviewer.com/.

3.10.7   Coin3D

Coin3D is an implementation of Open Inventor.

In Cgal, Coin3D is used in the demo of the Kinetic Data Structures package.

You can download it from http://www.coin3d.org/.

3.10.8   Estbl

The Estbl (Easy Structural Biology Template Library) is a library that allows the handling of Pdb data.

In Cgal the Estbl is used in an example of the 3D Skin Surface Meshing package.

It can be downloaded from http://esbtl.sourceforge.net/.

3.11   Building Cgal

The results of a successful configuration are build files that control the build step. The nature of the build files depends on the generator used during configuration, but in all cases they contain several targets, one per library, and a default global target corresponding to all the libraries.

For example, in a Unix-like environment the default generator produces makefiles. You can use the make command-line tool for the succeeding build step as follows:

cd CGAL-4.1

# build all the selected libraries at once

make 

The resulting libraries are placed in the subdirectory lib under <CMAKE_BINARY_DIR> (which is CGAL-4.1 in case you run an in-source-configuration).

With generators other than UNIX Makefiles the resulting build files are solution and project files which should be launched in an Ide, such as Visual Studio or KDevelop3. They will contain the targets described above, which you can manually build as with any other solution/project within your Ide.

Alternatively, you can build it with the command line version of the Visual Studio Ide:

    devenv CGAL.sln /Build Debug

The "Debug" argument is needed because CMake creates solution files for all four configurations, and you need to explicitly choose one when building (the other choices are Release, RelWithDebInfo and MinSizeRel).

If you have turned on the configuration of examples (-DWITH_examples=ON) and/or demos (-DWITH_demos=ON), there will be additional targets named examples and demos, plus one target for each example and each demo in the build files. None of these targets are included by default, so you need to build them explicitly after the Cgal libraries have been successfully built. The targets examples and demos include themselves all the targets for examples and demos respectively.

# build all examples at once
make examples 

# build all demos at once
make demos

# build only the Straight Skeleton demo
make Straight_skeleton_2_demo

3.12   Installing Cgal

On many platforms, library pieces such as headers, docs and binaries are expected to be placed in specific locations. A typical example being /usr/include and /usr/lib on Unix-like operating systems or C:/Program Files/ on Windows. The process of placing or copying the library elements into its standard location is sometimes referred to as Installation and it is a postprocessing step after the build step.

CMake carries out the installation by producing a build target named install. The following example shows a typical session from configuration to installation in a Unix-like environment:

cd CGAL-4.1

cmake .      # configure
make         # compile
make install # install

If you use a generator that produces IDE files (for Visual Studio for instance) there will be an optional INSTALL project, which you will be able to ``build'' to execute the installation step.

The file CGALConfig.cmake is installed by default in $CMAKE_INSTALLED_PREFIX/lib/CGAL-4.1.

3.13   Example Configuration

Below is an example output on a linux machine with g++4.4 installed, using CMake 2.8.5, and the following command-line call to cmake:

cmake -DWITH_examples=OFF -DWITH_demos=OFF -DCMAKE_BUILD_TYPE=Release 
  /path/to/unpacked/CGAL-tarball/

-- The CXX compiler identification is GNU
-- The C compiler identification is GNU
-- Check for working CXX compiler: /usr/bin/g++-4.4
-- Check for working CXX compiler: /usr/bin/g++-4.4 -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working C compiler: /usr/bin/gcc-4.4
-- Check for working C compiler: /usr/bin/gcc-4.4 -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
== Setting paths ==
== Build CGAL from release: CGAL-4.1 ==
-- Packagenames: CGAL-4.1
== Setting paths (DONE) ==

== Generate version files ==
-- CGAL_MAJOR_VERSION=4
-- CGAL_MINOR_VERSION=1
-- CGAL_BUGFIX_VERSION=0
-- CGAL_SONAME_VERSION=10
-- CGAL_SOVERSION     =10.0.0
-- CGAL_REFERENCE_CACHE_DIR=
-- Building shared libraries
-- Targetting Unix Makefiles
-- Using /usr/bin/g++-4.4 compiler.
-- USING CMake version: 2.8.5
-- System: Linux
-- USING GCC_VERSION = '4.4.5'
-- Using gcc version 4 or later. Adding -frounding-math
== Generate version files (DONE) ==

== Detect external libraries ==
-- Build type: Release
-- USING CXXFLAGS = ' -frounding-math -O3 -DNDEBUG'
-- USING LDFLAGS = '  '
-- External libraries supported: GMP;GMPXX;MPFR;zlib;OpenGL;LEDA;MPFI;RS;RS3;OpenNL;TAUCS;EIGEN3;BLAS;LAPACK;QGLViewer;ESBTL;NTL
-- Preconfiguring library: GMP ...
-- GMP has been preconfigured:
--   CGAL_UseGMP-file: 
--   GMP include:      /usr/include/
--   GMP libraries:    /usr/lib/libgmp.so
--   GMP definitions:  
-- USING GMP_VERSION = '4.3.2'
-- Preconfiguring library: GMPXX ...
-- GMPXX has been preconfigured:
--   CGAL_UseGMPXX-file: 
--   GMPXX include:      /usr/include
--   GMPXX libraries:    /usr/lib/libgmpxx.so
--   GMPXX definitions:  
-- Preconfiguring library: MPFR ...
-- MPFR has been preconfigured:
--   CGAL_UseMPFR-file: 
--   MPFR include:      /usr/include/
--   MPFR libraries:    /usr/lib/libmpfr.so
--   MPFR definitions:  
-- USING MPFR_VERSION = '3.0.0'
-- Boost version: 1.39.0
-- Found the following Boost libraries:
--   thread
-- Boost include:     /usr/include/boost_1_39_0/include/boost-1_39
-- Boost libraries:   /usr/lib/libboost_thread-mt.so;pthread
-- Boost definitions: 
-- USING BOOST_VERSION = '1.39.0'
== Detect external libraries (DONE) ==

== Write compiler_config.h ==
-- Performing Test CGAL_CFG_ARRAY_MEMBER_INITIALIZATION_BUG - Success
-- Performing Test CGAL_CFG_DENORMALS_COMPILE_BUG - Success
-- Performing Test CGAL_CFG_FPU_ROUNDING_MODE_UNWINDING_VC_BUG - Success
-- Performing Test CGAL_CFG_IEEE_754_BUG - Success
-- Performing Test CGAL_CFG_ISTREAM_INT_BUG - Success
-- Performing Test CGAL_CFG_LONGNAME_BUG - Success
-- Performing Test CGAL_CFG_MATCHING_BUG_5 - Success
-- Performing Test CGAL_CFG_MATCHING_BUG_6 - Success
-- Performing Test CGAL_CFG_NESTED_CLASS_FRIEND_DECLARATION_BUG - Success
-- Performing Test CGAL_CFG_NO_CPP0X_ARRAY - Failed
-- Performing Test CGAL_CFG_NO_CPP0X_AUTO - Failed
-- Performing Test CGAL_CFG_NO_CPP0X_COPY_N - Failed
-- Performing Test CGAL_CFG_NO_CPP0X_DECLTYPE - Failed
-- Performing Test CGAL_CFG_NO_CPP0X_DEFAULT_TEMPLATE_ARGUMENTS_FOR_FUNCTION_TEMPLATES - Failed
-- Performing Test CGAL_CFG_NO_CPP0X_DELEGATING_CONSTRUCTORS - Failed
-- Performing Test CGAL_CFG_NO_CPP0X_DELETED_AND_DEFAULT_FUNCTIONS - Success
-- Performing Test CGAL_CFG_NO_CPP0X_INITIALIZER_LISTS - Failed
-- Performing Test CGAL_CFG_NO_CPP0X_ISFINITE - Success
-- Performing Test CGAL_CFG_NO_CPP0X_LAMBDAS - Failed
-- Performing Test CGAL_CFG_NO_CPP0X_LONG_LONG - Success
-- Performing Test CGAL_CFG_NO_CPP0X_NEXT_PREV - Failed
-- Performing Test CGAL_CFG_NO_CPP0X_RVALUE_REFERENCE - Failed
-- Performing Test CGAL_CFG_NO_CPP0X_STATIC_ASSERT - Failed
-- Performing Test CGAL_CFG_NO_CPP0X_TUPLE - Failed
-- Performing Test CGAL_CFG_NO_CPP0X_VARIADIC_TEMPLATES - Failed
-- Performing Test CGAL_CFG_NO_LIMITS - Success
-- Performing Test CGAL_CFG_NO_LOGICAL_OPERATORS_ALTERNATIVES - Success
-- Performing Test CGAL_CFG_NO_MESSAGE_PRAGMA_BUG - Success
-- Performing Test CGAL_CFG_NO_NEXTAFTER - Success
-- Performing Test CGAL_CFG_NO_STATEMENT_EXPRESSIONS - Success
-- Performing Test CGAL_CFG_NO_STL - Success
-- Performing Test CGAL_CFG_NO_TR1_ARRAY - Success
-- Performing Test CGAL_CFG_NO_TR1_TUPLE - Success
-- Performing Test CGAL_CFG_NO_WARNING_CPP_DIRECTIVE_BUG - Success
-- Performing Test CGAL_CFG_NUMERIC_LIMITS_BUG - Success
-- Performing Test CGAL_CFG_OUTOFLINE_MEMBER_DEFINITION_BUG - Success
-- Performing Test CGAL_CFG_TEMPLATE_IN_DEFAULT_PARAMETER_BUG - Success
-- Performing Test CGAL_CFG_TYPENAME_BEFORE_DEFAULT_ARGUMENT_BUG - Success
-- Performing Test CGAL_CFG_USING_BASE_MEMBER_BUG_2 - Success
== Write compiler_config.h (DONE) ==

== Generating build files ==
-- Configure libCGAL
-- GMP include:     /usr/include/
-- GMP definitions: 
-- GMP libraries:   /usr/lib/libgmp.so
-- Configured GMP in standard way
-- MPFR include:     /usr/include/
-- MPFR definitions: 
-- MPFR libraries:   /usr/lib/libmpfr.so
-- Configured MPFR in standard way
-- libCGAL is configured
-- Sources for CGAL component library 'Core' detected
-- Configure libCGALCore
-- GMP include:     /usr/include/
-- GMP definitions: 
-- GMP libraries:   /usr/lib/libgmp.so
-- Configured GMP in standard way
-- MPFR include:     /usr/include/
-- MPFR definitions: 
-- MPFR libraries:   /usr/lib/libmpfr.so
-- Configured MPFR in standard way
-- libCGALCore is configured
-- Sources for CGAL component library 'Qt3' detected
-- Sources for CGAL component library 'Qt4' detected
-- Configure libCGALQt4
-- Looking for Q_WS_X11
-- Looking for Q_WS_X11 - found
-- Looking for Q_WS_WIN
-- Looking for Q_WS_WIN - not found.
-- Looking for Q_WS_QWS
-- Looking for Q_WS_QWS - not found.
-- Looking for Q_WS_MAC
-- Looking for Q_WS_MAC - not found.
-- Looking for XOpenDisplay in /usr/lib/libX11.so;/usr/lib/libXext.so
-- Looking for XOpenDisplay in /usr/lib/libX11.so;/usr/lib/libXext.so - found
-- Looking for gethostbyname
-- Looking for gethostbyname - found
-- Looking for connect
-- Looking for connect - found
-- Looking for remove
-- Looking for remove - found
-- Looking for shmat
-- Looking for shmat - found
-- Looking for IceConnectionNumber in ICE
-- Looking for IceConnectionNumber in ICE - found
-- Found X11: /usr/lib/libX11.so
-- USING QT4_VERSION = '4.6.3'
-- OpenGL include:     /usr/include
-- OpenGL libraries:   /usr/lib/libGLU.so;/usr/lib/libGL.so;/usr/lib/libSM.so;/usr/lib/libICE.so;/usr/lib/libX11.so;/usr/lib/libXext.so
-- OpenGL definitions: 
-- Qt4 include:        /usr/include/qt4
-- Qt4 libraries:      /usr/lib/libQtOpenGL.so;/usr/lib/libQtGui.so;/usr/lib/libQtCore.so
-- Qt4 definitions:    
-- moc executable:     /usr/bin/moc-qt4
-- uic executable:     /usr/bin/uic-qt4
-- GMP include:     /usr/include/
-- GMP definitions: 
-- GMP libraries:   /usr/lib/libgmp.so
-- Configured GMP in standard way
-- MPFR include:     /usr/include/
-- MPFR definitions: 
-- MPFR libraries:   /usr/lib/libmpfr.so
-- Configured MPFR in standard way
-- libCGALQt4 is configured
-- Sources for CGAL component library 'ImageIO' detected
-- Configure libCGALImageIO
-- Found OpenGL: /usr/lib/libGL.so 
-- Found ZLIB: /usr/lib/libz.so (found version "1.2.3.4")
-- OpenGL include:     /usr/include
-- OpenGL libraries:   /usr/lib/libGLU.so;/usr/lib/libGL.so;/usr/lib/libSM.so;/usr/lib/libICE.so;/usr/lib/libX11.so;/usr/lib/libXext.so
-- USING ZLIB_VERSION = '1.2.3.4'
-- libCGALImageIO is configured
-- Sources for CGAL component libraries 'CGAL;Core;ImageIO;Qt3;Qt4' detected
== Generating build files (DONE) ==

-- Configuring done
-- Generating done
-- Build files have been written to: /home/user/CGAL/4.1/

3.14   Multiple Variants of makefiles (out-of-source build)

While you can choose between release or debug builds, and shared or static libraries, it is not possible to generate different variants during a single configuration. You need to run CMake in a different directory for each variant you are interested in, each with its own selection of configuration parameters.

CMake stores the resulting makefiles and project files, along with several temporary and auxiliary files such as the variables cache, in the directory where it is executed, called CMAKE_BINARY_DIR, but it takes the source files and configuration scripts from CMAKE_SOURCE_DIR.

The binary and source directories do not need to be the same. Thus, you can configure multiple variants by creating a distinct directory for each configuration and by running CMake from there. This is known in CMake terminology as out-of-source configuration, as opposite to an in-source configuration, as showed in the previous sections.

You can, for example, generate subdirectories CGAL-4.1/cmake/platforms/debug and CGAL-4.1/cmake/platforms/release for two configurations, respectively:

mkdir CGAL-4.1/cmake/platforms/debug
cd CGAL-4.1/cmake/platforms/debug
cmake -DCMAKE_BUILD_TYPE=Debug ../../..

mkdir CGAL-4.1/cmake/platforms/release
cd CGAL-4.1/cmake/platforms/release
cmake -DCMAKE_BUILD_TYPE=Release ../../..

3.15   Configuring and Building Programs Using Cgal

Ideally, configuring and compiling a demo/example/program amounts to

cd CGAL-4.1/examples/Straight_skeleton_2
cmake -DCGAL_DIR=$HOME/CGAL-4.1 . 
make

In this ideal world, as for all shipped examples and demos of Cgal, the required CMakeLists.txt is already provided.

CMake can also be used to configure and build user programs via such CMake-scripts. In this less ideal world, one has to provide the CMakeLists.txt script either manually, or with the help of a shell-script that is introduced below.

For a user program executable.cpp, the ideal world looks like this:

cd /path/to/program 
cgal_create_CMakeLists -s executable
cmake -DCGAL_DIR=$HOME/CGAL-4.1 . 
make

In both examples we specify the CGAL_DIR: During configuration of the Cgal libraries a file named CGALConfig.cmake is generated in Cgal's root directory (in contrast to Cgal's source directory that has been used for installation). This file contains the definitions of several CMake variable that summarize the configuration of Cgal. In order to configure a program, you need to indicate the location of that config file in the CMake variable CGAL_DIR (as indicated in the example above). CGAL_DIR can also be an environment variable. Setting CGAL_DIR makes particular sense if having multiple out-of-source builds of Cgal as in Section 3.14.

If you have installed CGAL, CGAL_DIR must afterwards be set to $CMAKE_INSTALLED_PREFIX/lib/CGAL. Note that Cgal is recommended to be installed in release mode when using it to build programs.

3.15.1   Creating a cmake script for a program using Cgal

For compiling a non-shipped program, it is recommended, to also rely on a CMake-supported configuration using a CMakeLists.txt used for configuration.

Use the following Bourne-shell script for programs that are relatively simple to configure:

cgal_create_CMakeLists

The Bourne-shell script cgal_create_CMakeLists.txt resides in the CGAL-4.1/scripts directory. It can be used to create CMakeLists.txt files for compiling Cgal applications. Executing cgal_create_CMakeLists.txt in an application directory creates a CMakeLists.txt containing rules to build the contained application(s). Three command line options determine details of the configuration.

-s source

If this parameter is given the script will create a single executable for 'source' linked with compilations of all other source files (*.cpp). This behaviour is usually needed for (graphical) demos.
If the parameter is not given, the script creates one executable for each given source file.

-c com1:com2:...

Lists components (``com1'', ``com2'') of Cgal to which the executable(s) should be linked. Valid components are Cgal's libraries (i.e. ``Core'', ``ImageIO'', ``Qt3'' and ``Qt4''; note that it only make sense to either pick ``Qt3'' or ``Qt4'') and all preconfigured 3rd party software, such as ``MPFI'' or ``RS3'' ). An example is -c Core:GMP:RS3:MPFI

-b boost1:boost2:...

Lists components (``boost1'', ``boost2'') of Boost to which the executable(s) should be linked. Valid options are, for instance, ``filesystem'' or ``program_options''.

This options should suffice to create CMakeLists.txt script for most directories containing programs. However, in some special cases, it might still be required to create the script manually, for instance, if some source files/executables need a different linking than other source files.

Such a shell-script simply creates a CMake script. Processing it with CMake, searches for Cgal using find_package. If found, the variable CGAL_USE_FILE is set to a compilation environment CMake file. Including this file within a CMake script sets up include paths and libraries to link with Cgal and essential third party libraries. Beyond, find_package can demand for COMPONENTS of Cgal, that is, all Cgal libraries libCGAL_Core (``Core''), libCGAL_imageIO (``ImageIO'') , libCGAL_Qt3 (``Qt3'') and libCGAL_Qt4 (``Qt4'') or optional 3rd party software such as ``MPFI'' or ``RS3''. A user is free to create the CMakeLists.txt without calling the script (manual creation).

3.15.2   Custom flags in the programs using Cgal

Normally, programs linked with Cgal must be compiled with the same flags used by the compilation of Cgal libraries. For this reason, the very first time a program is configured, all the flags given by the CMake variables CMAKE_*_FLAGS are locked in the sense that the values recorded in CGALConfig.cmake are used to override any values given by CMake itself or yourself.

This does not apply to the additional flags that can be given via CGAL_*_FLAGS.

Such inherited values are then recorded in the current CMake cache for the program. The flags are then unlocked in the sense that at any subsequent configuration you can provide your own flags and this time they will not be overridden.

When using the interactive cmake-gui the first press on Configure unlocks the flags, so that you can edit them as needed.

cd CGAL-4.1

cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_CXX_FLAGS=-g .

cd CGAL-4.1/examples/Straight_skeleton_2

cmake -DCGAL_DIR=CGAL-4.1 -DCMAKE_BUILD_TYPE=Debug -DCMAKE_CXX_FLAGS=-O2 -DCGAL_DONT_OVERRIDE_CMAKE_FLAGS=TRUE . 

3.16   Summary of Cgal's Configuration Variables

Most configuration variables are not environment variables but CMake variables. They are given in the command line to CMake via the -D option, or passed from the interactive interface of cmake-gui. Unless indicated differently, all the variables summarized below are CMake variables.

3.16.1   Component selection

The following boolean variables indicate which Cgal components to configure and build. Their values can be ON or OFF.

3.16.2   Compiler and Linker Flags

The following variables specify compiler and linker flags. Each variable holds a space-separated list of command-line switches for the compiler and linker and their default values are automatically defined by CMake based on the target platform.

Have in mind that these variables specify a list of flags, not just one single flag. If you provide your own definition for a variable, you will entirely override the list of flags chosen by CMake for that particular variable.

The variables that correspond to both debug and release builds are always used in conjunction with those for the specific build type.

Additional Compiler and Linker Flags

The following variables can be used to add flags without overriding the ones defined by cmake.

3.16.3   Miscellaneous Variables

Variables used only when building programs (such as demos or examples)

3.16.4   Variables providing information about 3rd-party libraries

The following variables provide information about the availability and location of the 3rd party libraries used by Cgal. CMake automatically searches for dependencies so you need to specify these variables if CMake was unable to locate something. This is indicated by a value ending in NOTFOUND.

Since 3rd-party libraries are system wide, many of the CMake variables listed below can alternatively be given as similarly-named environment variables instead. Keep in mind that you must provide one or the other but never both.

Boost libraries

In most cases, if Boost is not automatically found, setting the BOOST_ROOT variable is enough. If it is not, you can specify the header and library directories individually. You can also provide the full pathname to a specific compiled library if it cannot be found in the library directory or its name is non-standard.

By default, when Boost binary libraries are needed, the shared versions are used if present. You can set the variable CGAL_Boost_USE_STATIC_LIBS to ON if you want to link with static versions explicitly.

On Windows, if you link with Boost shared libraries, you must ensure that the .dll files are found by the dynamic linker, at run time. For example, you can add the path to the Boost .dll to the PATH environment variable.

Gmp and Mpfr libraries

Under Windows, auto-linking is used, so only the directory containing the libraries is needed and you would specify GMP|MPFR_LIBRARY_DIR rather than GMP|MPFR_LIBRARIES. On the other hand, under Linux the actual library filename is needed. Thus you would specify GMP|MPFR_LIBRARIES. In no case you need to specify both.

Cgal uses both Gmp and Mpfr so both need to be supported. If either of them is unavailable the usage of Gmp and of Mpfr will be disabled.

Under Linux, the Gmpxx is also searched for, and you may specify the following variables:

Qt3 library

In most cases, if Qt3 is not automatically found, setting the QTDIR environment variable is sufficient. If it is not, you can specify the directory containing the header files and the full pathnames of the Qt3 libraries.

Qt4 library

The CMake scripts that search for Qt4 can use the introspection feature of the tool qmake included in Qt4 distributions. If Qt4 is not automatically found, it is sufficient to set the PATH environment variable, so that Qt4 qmake tool is in the path, and before Qt3 qmake if that one exists. One can alternatively set the CMake variable QT_QMAKE_EXECUTABLE. The following variables should be then assigned automatically by CMake.

Leda library

When the Leda libraries are not automatically found, yet they are installed on the system with base names 'leda' and 'ledaD' (for the release and debug versions resp.), it might be sufficient to just indicate the library directory via the LEDA_LIBRARY_DIRS variable. If that doesn't work because, for example, the names are different, you can provide the full pathnames of each variant via LEDA_LIBRARY_RELEASE and LEDA_LIBRARY_DEBUG.

The variables specifying definitions and flags can be left undefined if they are not needed by Leda.

Mpfi library

Cgal provides a number type based on this library, but the Cgal library itself does not depend on Mpfi. This means that this library must be configured when compiling an application that uses the above number type.

When Mpfi files are not on the standard path, the locations of the headers and library files must be specified by using environment variables.

Rs and Rs3 library

As said before, only the Cgal univariate algebraic kernel depends on the library Rs. As the algebraic kernel is not compiled as a part of the Cgal library, this library is not detected nor configured at installation time.

CMake will try to find Rs in the standard header and library directories. When it is not automatically detected, the locations of the headers and library files must be specified using environment variables.

Rs needs Gmp 4.2 or later and Mpfi 1.3.4 or later. The variables related to the latter library may also need to be defined.

Similar variables exist for Rs3.

Ntl library

Some polynomial computations in Cgal's algebraic kernel are speed up when Ntl is available. As the algebraic kernel is not compiled as a part of the Cgal library, this library is not detected nor configured at installation time.

CMake will try to find Ntl in the standard header and library directories. When it is not automatically detected, the locations of the headers and library files must be specified using environment variables.

Eigen library

Eigen is a header-only template library. Only the directory containing the header files of Eigen 3.1 (or greater) is needed.

QGLViewer library

Some demos require the GLViewer library.

In most cases, if QGLViewer is not automatically found, setting the QGLVIEWERROOT environment variable is sufficient. If it is not, you can specify the directory containing the header files and the full pathnames of the release and debug libraries

ESBTL library

One skin surface example requires the ESBTL library in order to read Pdb files.

If ESBTL is not automatically found, setting the ESBTL_INC_DIR environment variable is sufficient.

3.17   Compiler Workarounds

A number of boolean flags are used to workaround compiler bugs and limitations. They all start with the prefix CGAL_CFG. These flags are used to work around compiler bugs and limitations. For example, the flag CGAL_CFG_NO_CPP0X_LONG_LONG denotes that the compiler does not know the type long long.

For each installation a file <CGAL/compiler_config.h> is defined, with the correct settings of all flags. This file is generated automatically by CMake, and it is located in the include directory of where you run CMake. For an in-source configuration this means CGAL-x.y/include.

The test programs used to generate the compiler_config.h file can be found in config/testfiles. Both compiler_config.h and the test programs contain a short description of the problem. In case of trouble with one of the CGAL_CFG flags, it is a good idea to take a look at it.

The file CGAL/compiler_config.h is included from <CGAL/config.h>. which is included by all Cgal header files.

3.18   Compiler Optimizations

By default CMake generates makefiles for Release mode, with optimization flags switched on, and vcproj files for Release and Debug modes.

Footnotes