Purpose: to document the use of another of the [magic names]
in Tcl. More formally, TCLLIBPATH is an ''environment'' variable; inside Tcl you can retrieve it with $::env(TCLLIBPATH).

**What is its purpose?**

To provide user specified locations to add to the package search path.

**What is the relationship between TCLLIBPATH and Tcl's ::[auto_path] variable?**

**What is its format?**

A tcl [list] of directory paths (unix-style paths for Win32 users). e.g: 
======
set TCLLIBPATH [list /opt/tcl/site-lib /users/pat/working]
======

**What are some good reasons to set it?**

   * site specific packages

[PT] 20-Jul-2004: 
I like to keep all my local packages separate from the ActiveTcl installation that I use as a 
base. So I install all additional packages to a ''site-lib'' directory and then set TCLLIBPATH
to this directory path. With this in place a [[package require XYZ]] command will search ActiveTcl 
'''and''' my ''site-lib'' directory for the most recent version of XYZ.

   * test a package without installing. 


**Questions relating to TCLLIBPATH**

***Why don't I see TCLLIBPATH set in my program?***

[D. McC] 08-Nov-2004:
Well ... what about this?

 [david@localhost david]% puts $::env(HOME)

/home/david

 [david@localhost david]% puts $::env(TCLLIBPATH)

can't read "::env(TCLLIBPATH)": no such variable

This happens on my Mandrake linux 10.0 system, running Tcl 8.4 from the tcl-8.4.5-3mdk RPM package. Why no TCLLIBPATH, I wonder?

[RS]: Because nobody has set it? :-) Normally it's best to use as few env variables as possible - it should only be used to override some default behavior, which for finding libs is: 
 [file dir [info nameofexe]]/../lib
and similar variations.

[LV] David, environmental variables are ones that someone external to Tcl set.
In many cases, they are set by a user.  In a few cases, a shell command or some other
utility (such as [Modules] for instance), may set the environment variables.
So many times, one won't find them set.  This is different than ''magic names'' like
the $argc variable, etc.

*** What specific path goes into the TCLLIBPATH? ***

[LV] 2009-Jun-29

I download a package onto my machine. The package has a README, a demo directory, a lib directory, etc. Within the lib directory I see 3 sub-directories, and within the sub-directories are the [pkgIndex.tcl] file, etc. 

So the basic layout is:
===
Installation directory/
 README.txt
 demos/
 lib/
  package1/
    pkgIndex.tcl 
  package2/
    pkgIndex.tcl
  package3/
    pkgIndex.tcl
 src/
 tests/
======

So, what path(s) go into TCLLIBPATH? the path to the lib/ , or each of the individual packages?

Thanks!

[PT]: the lib directory.

[LV] PT, thank you for the answer. I tried using that, and ran into my long time nemesis - Windows folders with spaces in the names. 
So eventually, when I have time, I need to change to using [file join] to set the TCLLIBPATH rather than just hard coding the path, so that it has some chance of working.  

----

See also [TCL_LIBRARY], [auto_path].

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'''[msubbareddy] - 2010-08-03 14:27:14'''

msubbareddy: 
****List the installed libraries on linux tcl platform as teacup does on Windows ActiveTcl****

ls -l [list [file dirname [info library]]]

----
[LGT] Example on Windows with Git-1.7.7.1-preview20111027

 $ unset TCLLIBPATH
 $ TCLLIBPATH=". C:/Tcl/lib"
 $ export TCLLIBPATH
 $ tclsh
 % package require Expect
 can't find package Expect
 % exit
 $ TCLLIBPATH=" . C:/Tcl/lib "
 $ export TCLLIBPATH
 $ tclsh
 % package require Expect
 5.43.2
 % exit
 $

Spaces seem to be required at the beginning of TCLLIBPATH value... 

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