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 its format?'''

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

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

[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. 

'''What else?'''

[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.

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See also [TCL_LIBRARY]

[[ [Category Tutorial] ]]