# Appendix A: Install and Build ROOT
\index{install ROOT}

## License


ROOT is made available under the LGPL v2.1 license. For full details see
the file LICENSE in the ROOT distribution.

## Installing ROOT


To install ROOT you will need to go to the ROOT website at:
<https://root.cern/install/>

You have a choice to download the binaries or the source. The source is
quicker to transfer since it is only 31 MB, but you will need to compile
and link it. The binaries range from 50 MB to 100 MB depending on the
target platform.

## Choosing a Version


The ROOT developers follow the principle of "release early and release
often", however a very large portion of a user base requires a stable
product therefore generally three versions of the system is available
for download - new, old and pro:

-   The *new* version evolves quickly, with weekly or bi-weekly
    releases. Use this to get access to the latest and greatest, but it
    may not be stable. By trying out the new version you can help us
    converge quickly to a stable version that can then become the new
    pro version. If you are a new user we would advice you to try the
    new version.

-   The *pro* (production) version is a version we feel comfortable with
    to exposing to a large audience for serious work. The change rate of
    this version is much lower than for the new version, it is about 3
    to 6 months.

-   The *old* version is the previous pro version that people might need
    for some time before switching the new pro version. The old change
    rate is the same as for pro.

## Installing Precompiled Binaries


The binaries are available for downloading from
<https://root.cern/install/>. Once downloaded
you need to unzip and de-tar the file. For example, if you have
downloaded ROOT v5.30 for Linux-SLC5:

``` {.cpp}
% gunzip root_v5.30.00.Linux-slc5-gcc4.3.tar.gz
% tar xvf root_v5.30.00.Linux-slc5-gcc4.3.tar
```

This will create the directory root. Before getting started read the
file README/README. Also, read the Introduction chapter for an
explanation of the directory structure.

## Installing from the Source

The ROOT's source code sits in the GitHub repository <https://github.com/root-project/root>
all the details and options to buld ROOT from sources are given in
<https://root.cern/building-root>

In short, the steps to build ROOT from the sources are the following:

  1. Clone the repository:
``` {.cpp}
$ git clone https://github.com/root-project/root.git
```

  2. Make a directory for building
``` {.cpp}
$ mkdir build
$ cd build
```

  3. Run cmake and make
``` {.cpp}
$ cmake ../root
$ make -j8
```

  4. Setup and run ROOT
``` {.cpp}
$ source bin/thisroot.sh
$ root
```

#### Staying up-to-date

To keep your local ROOT source up-to-date with the GitHub repository
you should regularly run the command:

``` {.cpp}
% git pull
```

## File system.rootrc


ROOT Environment settings are handled via the class **`TEnv`**.
`gEnv->Print()`shows which values are active. Any settings can be
obtained by `TEnv::GetValue` methods that return an integer, double or
character value for a named resource. If the resource is not found, the
default value (given as the second parameter) is returned.

``` {.cpp}
fShowEventStatus = gEnv->GetValue("Canvas.ShowEventStatus",kFALSE);
```

Via the method `TEnv::SetValue` allows you can set the value of a
resource or create a new resource:

``` {.cpp}
gEnv->SetValue("Root.ObjectStat",1);
```

Path used by dynamic loader to find shared libraries and macros. Paths
are different for Unix and Windows. The example shows the defaults for
all ROOT applications for either Unix or Windows:

``` {.cpp}
Unix.*.Root.DynamicPath:    .:$(ROOTSYS)/lib
Unix.*.Root.MacroPath:      .:$(ROOTSYS)/macros
WinNT.*.Root.DynamicPath:   .;$(ROOTSYS)/bin;$(PATH)
WinNT.*.Root.MacroPath:     .;$(ROOTSYS)/macros
```

Path where to look for `TrueType` fonts:

``` {.cpp}
Unix.*.Root.UseTTFonts:     true
*.*.Root.TTFontPath:        $(ROOTSYS)/fonts
```

Use `Net* API` functions:

``` {.cpp}
WinNT.UseNetAPI:            true
```

Use thread library (if exists).

``` {.cpp}
Unix.*.Root.UseThreads:     false
```

Select the compression algorithm (0=old zlib, 1=new zlib). Setting this
to \`0' may be a security vulnerability.

``` {.cpp}
Root.ZipMode:               1
```

Show where item is found in the specified path:

``` {.cpp}
Root.ShowPath:              false
```

Activate memory statistics.

``` {.cpp}
Root.ObjectStat:            0
```

Global debug mode. When `>0` turns on progressively more details
debugging.

``` {.cpp}
Root.Debug:                 0
Root.Stacktrace:            yes
```

Settings for X11 behaviour.

``` {.cpp}
X11.Sync:                   no
X11.FindBestVisual:         yes
```

Default editor in use.

``` {.cpp}
Unix.*.Editor:              vi
WinNT.*.Editor:             notepad
```

Default 3d Viewer. By default 3-D views are shown in the pad, if the
next line is activated, the default viewer will be OpenGL.

``` {.cpp}
Viewer3D.DefaultDrawOption: ogl
```

Default Fitter (current choices are `Minuit`, `Minuit2`, `Fumili` and
`Fumili2`).

``` {.cpp}
Root.Fitter:                Minuit
```

Specify list of file endings which **`TTabCom`** (TAB completion) should
ignore.

``` {.cpp}
TabCom.FileIgnore:          .cpp:.h:.cmz
```

### TCanvas Specific Settings


Opaque move and resize show full pad during the operation instead of
only the outline. Especially for resize you will need serious CPU power.
`UseScreenFactor=true` means to size canvas according to size of screen,
so a canvas still looks good on a low resolution laptop screen without
having to change canvas size in macros.

``` {.cpp}
Canvas.MoveOpaque:          false
Canvas.ResizeOpaque:        false
Canvas.UseScreenFactor:     true
```

Hight color 2 is the red one.

``` {.cpp}
Canvas.HighLightColor:      2
```

Next three settings are related to different user interface parts of
canvas window. If they are set to true, the corresponding event status
bar, tool bar, graphics editor will be activated by default.

``` {.cpp}
Canvas.ShowEventStatus:     false
Canvas.ShowToolBar:         false
Canvas.ShowEditor:          false
```

AutoExec allows **`TExec`** objects to be executed on mouse and key
events.

``` {.cpp}
Canvas.AutoExec:            true
```

Canvas print directory is set to the current one by default:

``` {.cpp}
Canvas.PrintDirectory     .
```

Printer settings:

``` {.cpp}
WinNT.*.Print.Command:    AcroRd32.exe
#Unix.*.Print.Command:    a2ps -P%p --landscape --columns=2 --margin=30 -rf8.0 %f
Print.Printer:            32-rb20-hp
Print.Directory:          .
Print.FileType:           pdf
```

Default histogram binnings used by `TTree::Draw()` method.

``` {.cpp}
Hist.Binning.1D.x:          100
Hist.Binning.2D.x:           40
Hist.Binning.2D.y:           40
Hist.Binning.2D.Prof:       100
Hist.Binning.3D.x:           20
Hist.Binning.3D.y:           20
Hist.Binning.3D.z:           20
Hist.Binning.3D.Profx:      100
Hist.Binning.3D.Profy:      100
```

Default statistics names used for parameters in **`TPaveStats`**:

``` {.cpp}
Hist.Stats.Entries         Entries
Hist.Stats.Mean            Mean
Hist.Stats.MeanX           Mean x
Hist.Stats.MeanY           Mean y
Hist.Stats.RMS             RMS
Hist.Stats.RMSX            RMS x
Hist.Stats.RMSY            RMS y
Hist.Stats.Underflow       Underflow
Hist.Stats.Overflow        Overflow
Hist.Stats.Integral        Integral
Hist.Stats.Skewness        Skewness
Hist.Stats.SkewnessX       Skewness x
Hist.Stats.SkewnessY       Skewness y
Hist.Stats.Kurtosis        Kurtosis
Hist.Stats.KurtosisX       Kurtosis x
Hist.Stats.KurtosisY       Kurtosis y
```

### THtml Specific Settings


See the reference guide documentation of **`THtml`** class at
<http://root.cern.ch/root/htmldoc/THtml.html> for more details.

XHTML content charset (see
<http://www.w3.org/TR/2002/REC-xhtml1-20020801>, default: ISO-8859-1) is
set by:

``` {.cpp}
Root.Html.Charset:
```

Stem of a search engine for the documentation, where `%s` is replaced by
the term entered in the search text box (example:
`http://www.google.com/search?q=%s+site%3Aroot.cern.ch%2Froot%2Fhtml`,
default is `""`)

``` {.cpp}
Root.Html.Search:
```

Link to the site's search engine (default: `""`, example:
`http://root.cern.ch/root/Search.phtml`)

``` {.cpp}
Root.Html.SearchEngine:
```

String to prepend to `TClass::GetImplFileName()` names containing
directories when looking for source files (default: `""`, `e`xample:
`../root`)

``` {.cpp}
Root.Html.SourcePrefix:
```

Link stem to `ViewCVS` entry for classes, where a class name is assumed
to match a file name (default: `""`, example:
`http://root.cern.ch/viewcvs`).

``` {.cpp}
Root.Html.ViewCVS:
```

Stem of the CERN XWho system (default:
`http://consult.cern.ch/xwho/people?`)

``` {.cpp}
Root.Html.XWho:
```

If set to Doc++, allow method documentation in front of method even for
methods in the source file (default: `""`)

``` {.cpp}
Root.Html.DescriptionStyle:
```

Search path for the source and header files with their default settings:

``` {.cpp}
Unix.*.Root.Html.SourceDir:  .:src:include
WinNT.*.Root.Html.SourceDir: .;src;include
```

URL stem for ROOT documentation pages (default is `""`).

``` {.cpp}
Root.Html.Root:              http://root.cern.ch/root/html
```

Filesystem output directory for generated web pages (default:
`htmldoc)`.

``` {.cpp}
Root.Html.OutputDir:        htmldoc/
```

Address of the package's home page (default: <http://root.cern.ch>):

``` {.cpp}
Root.Html.HomePage:
```

Location of user defined header and footer files, see
<http://root.cern.ch/root/html/THtml#conf:header> (defaults are `""`,
example: `../header.txt`, `../footer.txt`):

``` {.cpp}
Root.Html.Header:
Root.Html.Footer:
```

Tag for detecting class description comments (default value is set
below).

``` {.cpp}
Root.Html.Description:      //____________________
```

Tag for detecting "Author" comment (default value is set below).

``` {.cpp}
Root.Html.Author:           // Author:
```

Tag for detecting "last updated" comment. **`THtml`** uses the current
date if this tag is not found in a class source file (default value is
set below).

``` {.cpp}
Root.Html.LastUpdate:       // @(#)
```

Tag for detecting "Copyright" comment (default value is set below).

``` {.cpp}
Root.Html.Copyright:        * Copyright
```

### GUI Specific Settings


Set the "`native`" ROOT GUI interface to be used in a ROOT session.

``` {.cpp}
Gui.Backend:                native
Gui.Factory:                native
```

GUI default fonts in use:

``` {.cpp}
Gui.DefaultFont:            -adobe-helvetica-medium-r-*-*-12-*-*-*-*-*-iso8859-1
Gui.MenuFont:               -adobe-helvetica-medium-r-*-*-12-*-*-*-*-*-iso8859-1
Gui.MenuHiFont:             -adobe-helvetica-bold-r-*-*-12-*-*-*-*-*-iso8859-1
Gui.DocFixedFont:           -adobe-courier-medium-r-*-*-12-*-*-*-*-*-iso8859-1
Gui.DocPropFont:            -adobe-helvetica-medium-r-*-*-12-*-*-*-*-*-iso8859-1
Gui.IconFont:               -adobe-helvetica-medium-r-*-*-10-*-*-*-*-*-iso8859-1
Gui.StatusFont:             -adobe-helvetica-medium-r-*-*-10-*-*-*-*-*-iso8859-1
```

Regular background and foreground colors in use:

``` {.cpp}
Gui.BackgroundColor:         #c0c0c0
Gui.ForegroundColor:         black
```

Selection background and foreground colors in use:

``` {.cpp}
Gui.SelectBackgroundColor:   #000080
Gui.SelectForegroundColor:   white
```

Document background and foreground colors in use:

``` {.cpp}
Gui.DocumentBackgroundColor: white
Gui.DocumentForegroundColor: black
```

Tooltip background and foreground colors in use:

``` {.cpp}
Gui.TooltipBackgroundColor:  LightYellow
Gui.TooltipForegroundColor:  black
```

Path where all GUI icons in use can be found:

``` {.cpp}
Gui.IconPath:                $(HOME)/icons:$(ROOTSYS)/icons:.
```

Mime type file setting:

``` {.cpp}
Gui.MimeTypeFile:            $(HOME)/.root.mimes
```

If `$(HOME)/.root.mimes` does not exists, defaults to this:

``` {.cpp}
#Gui.MimeTypeFile:            $(ROOTSYS)/etc/root.mimes
```

### TBrowser Settings


Current icon style selection - can be either `small`, `big`, `list`,
`details`:

``` {.cpp}
Browser.IconStyle:           small
```

Current sorting rule applied on the browser objects - can be `name`,
`type`, `size`, `date`:

``` {.cpp}
Browser.SortBy:              name
```

Number of items in a group view:

``` {.cpp}
Browser.GroupView:           10000
```

Show or not hidden items:

``` {.cpp}
Browser.ShowHidden:          no
```

Create a thumbnail view after executing the macro (default is `yes`).

``` {.cpp}
Browser.AutoThumbnail:       yes
```

### TRint Specific Settings


Rint (interactive ROOT executable) specific alias, logon and logoff
macros.

``` {.cpp}
Rint.Load:               rootalias.C
Rint.Logon:              rootlogon.C
Rint.Logoff:             rootlogoff.C
```

Record ROOT session commands in a given history file (default is
`$(HOME)/.root_hist`). If set to "`-`", it turn off the command
recording.

``` {.cpp}
Rint.History:            $(HOME)/.root_hist
```

Next two lines set the history file size handling. Once `HistSize` is
reached, the last `HistSave` entries are removed. If `HistSize` is set
to 0, it turns off command recording. Both values can be overridden by
environment variable `ROOT_HIST=size[:save]`, where the "`:save`" part
is optional.

``` {.cpp}
Rint.HistSize:         500
Rint.HistSave:         400
```

### ACLiC Specific Settings


`ACLiC.Linkdef` specifies the suffix that will be added to the script
name to try to locate a custom linkdef file when generating the
dictionary.

``` {.cpp}
ACLiC.Linkdef:          _linkdef
```

The top directory for storing the libraries produced by ACLiC is set by:

``` {.cpp}
ACLiC.BuildDir:        /where/I/would/like/my/compiled/scripts
```

The additional include directives for ACLiC compilations are set by:

``` {.cpp}
ACLiC.IncludePaths:     -I/where/the/includes/are
```

### PROOF Related Variables


PROOF debug options.

``` {.cpp}
Proof.DebugLevel: 0
Proof.DebugMask:-1
```

PROOF GDB hooks allows a debugger to be attached early in the startup
phase of `proofserv: `0 - don't wait; 1 - master proofserv enters wait
loop; 2 - slave proofserv enters wait loop; 3 - any proofserv enters
wait loop

``` {.cpp}
Proof.GdbHook:    0
```

On the master to enable the parallel startup of workers using threads
set next to "`yes`" (default is "`no`"):

``` {.cpp}
Proof.ParallelStartup: no
```

``` {.cpp}
Proof.StatsHist:       no
Proof.StatsTrace:      no
Proof.SlaveStatsTrace: no
```

``` {.cpp}
Proof.CondorHome:     /opt/condor
Proof.CondorConfig:   /opt/condor/etc/condor_config
```

``` {.cpp}
PEAC.GmUrl:           http://somewhere:8080/clarens/
PEAC.LmUrl:           http://elsewhere:8080/clarens/
```

#### Server Authentication in TServerSocket

General setting: file with server access rules

``` {.cpp}
SrvAuth.DaemonRc:        /etc/root/system.daemonrc
```

Check of host equivalence via `/etc/hosts`.`equiv` or `$HOME/.rhosts`.

``` {.cpp}
SrvAuth.CheckHostsEquivalence: 1
```

Force file opening via **`TNetFile`** (**`TXNetFile`**) if a hostname is
specified in the Url. By default, for local files `TFile::Open()`
invokes directly **`TFile.`**

``` {.cpp}
TFile.ForceRemote:        yes
```

Special cases for the **`TUrl`** parser, where the special cases are
parsed in a protocol + file part, like rfio:host:/path/file.root,
castor:/path/file.root or /alien/path/file.root. In case the file
namespace descriptor ends with - the namespace is not a part of the
filename. Extend in private .rootrc with a +Url.Special line.

``` {.cpp}
Url.Special:             file: rfio: hpss: castor: dcache:
+Url.Special:            /alien/- /castor/
```

#### PROOF XRD Client Variables

Debug level (if \<=0 : none, 1 : low, 2 : medium, 3 : high)

``` {.cpp}
XProof.Debug:       0
```

Socket read timeout [in secs: default 10 secs]

``` {.cpp}
XProof.ReadTimeout: 10
```

The following env vars are handled by **`TXNetFile`** and related
classes (module `netx`, `libNetx.so`).

`XNet.ConnectTimeout` - maximum time to wait before server's response on
a connect [10 s]

`XNet.RequestTimeout` - maximum time to wait before considering a
read/write failure [60 s]

`XNet.ConnectDomainAllowRE` - sequence of **`TRegexp`** regular
expressions separated by a `|`. A domain is granted access to for the
first connection if it matches one of these regexps. Example:

``` {.cpp}
slac.stanford.edu|pd.infn.it|fe.infn.it
```

`XNet.ConnectDomainDenyRE` - sequence of TRegexp regular expressions
separated by a `|`. A domain is denied access to for the first
connection if it matches one of these regexps.

`XNet.RedirDomainAllowRE` - sequence of TRegexp regular expressions
separated by a `|`. A domain is granted access to for a redirection if
it matches one of these regexps. Example:

`XNet.RedirDomainDenyRE` - sequence of TRegexp regular expressions
separated by a `|`. A domain is granted access to for a redirection if
it matches one of these regexps.

`XNet.MaxRedirectCount` - maximum number of redirections from server
[default - 255]

`XNet.Debug` - log verbosity level (0=nothing,1=messages of interest to
the user, 2=messages of interest to the developers (includes also user
messages), 3=dump of all sent/received data buffers (includes also user
and developers messages). [default - 0]

`XNet.ReconnectTimeout` - sleep-time before going back to the load
balancer (or rebouncing to the same failing host) after a read/write
error [default - 10s]

`XNet.StartGarbageCollectorThread` - for test/development purposes.
Normally nonzero (true), but as workaround for external causes someone
could be interested in not having the garbage collector thread around.
[experimental!]

`XNet.GoAsynchronous` - default is 0. When activated, **`XTNetFile`**
works in async mode, allowing input buffering and unsolicited responses
[experimental!]

`XNet.TryConnect` - Number of tries connect to a single server before
giving up.

`XNet.TryConnectServersList` - number of connect retries to the whole
server list given [default - 240]

`XNet.PrintTAG` - Print a particular string the developers can choose to
quickly recognize the version at run time [default - 0]

Example of custom setting for the Rint application (root.exe). This
overrides the default specified above for a generic application. Color 5
is yellow.

``` {.cpp}
Rint.Canvas.HighLightColor:      5
```

## Documentation to Download


-   The latest ROOT Users Guide

-   <https://root.cern.ch/root/htmldoc/guides/users-guide/ROOTUsersGuide.html>

-   ROOT Reference Guide

-   <http://root.cern.ch/root/Reference.html>