| ActiveTcl User Guide |

## Tcl/Tk Documentation > TkCmd > tkvars

### Tcl/Tk Applications | Tcl Commands | Tk Commands | Tcl Library | Tk Library

### NAME

tkvars - Variables used or set by Tk

### DESCRIPTION

The following Tcl variables are either set or used by Tk at various times in its execution:

tk_library
  This variable holds the file name for a directory containing a library of Tcl scripts related to Tk. These scripts include an initialization file that is normally processed whenever a Tk application starts up, plus other files containing procedures that implement default behaviors for widgets. The initial value of tcl_library is set when Tk is added to an interpreter; this is done by searching several different directories until one is found that contains an appropriate Tk startup script. If the TK_LIBRARY environment variable exists, then the directory it names is checked first. If TK_LIBRARY is not set or does not refer to an appropriate directory, then Tk checks several other directories based on a compiled-in default location, the location of the Tcl library directory, the location of the binary containing the application, and the current working directory. The variable can be modified by an application to switch to a different library.
tk_patchLevel
  Contains a decimal integer giving the current patch level for Tk. The patch level is incremented for each new release or patch, and it uniquely identifies an official version of Tk.
tk::Priv
  This variable is an array containing several pieces of information that are private to Tk. The elements of tk::Priv are used by Tk library procedures and default bindings. They should not be accessed by any code outside Tk.
tk_strictMotif
  This variable is set to zero by default. If an application sets it to one, then Tk attempts to adhere as closely as possible to Motif look-and-feel standards. For example, active elements such as buttons and scrollbar sliders will not change color when the pointer passes over them.
tk_textRedraw
tk_textRelayout
  These variables are set by text widgets when they have debugging turned on. The values written to these variables can be used to test or debug text widget operations. These variables are mostly used by Tk's test suite.
tk_version
  Tk sets this variable in the interpreter for each application. The variable holds the current version number of the Tk library in the form major.minor. Major and minor are integers. The major version number increases in any Tk release that includes changes that are not backward compatible (i.e. whenever existing Tk applications and scripts may have to change to work with the new release). The minor version number increases with each new release of Tk, except that it resets to zero whenever the major version number changes.

### KEYWORDS

variables, version, text
Copyright © 1995-1997 Roger E. Critchlow Jr. Copyright © 1990-1994 The Regents of the University of California. Copyright © 1994-1996 Sun Microsystems, Inc.