tkvars - Variables used or set by Tk
The following Tcl variables are either set or used by Tk at various times in its
- 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.
- 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.
- 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
- 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.
- 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
- 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.
variables, version, text