# 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 name of 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. If the variable isn't already set when a Tk application is created, Tk sets it from the TK_LIBRARY environment variable, if one exists, or else from a default value compiled into Tk. 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.

tkPriv
  This variable is an array containing several pieces of information that are private to Tk. The elements of tkPriv 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_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