The following Tcl variables are either set or used by Tk at various times in its execution:
- 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 isn't set or doesn't 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 outside Tk.
- 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 suite.
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.
KEYWORDSvariables, version, text