Tcl/Tk 9.1
Latest Release: Tcl/Tk 9.1.0 (Sep 29, 2026)
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Tcl/Tk 9.1.0 is the current development work on
Tcl/Tk 9.1.0 is the current development work on Tcl and Tk, aiming toward stable releases in September 2026. They add new features and interfaces to the foundation of Tcl/Tk 9.0. New command unicode: Unicode normalization New C routines Tcl_UtfToNormalized*: Unicode normalization New command timer: monotonic clock; microsecond resolution New command lfilter: select items from list New command interp set: variable access in child interpreter New subst options: -backslashes, -commands, -variables. New switch options: -integer. Many C99 math routines now available as expr functions. Applications now required to call an initialization routine, either Tcl_FindExecutable or TclZipfs_AppHook. New C routine Tcl_IsEmpty. New C routine Tcl_GetEncodingNameForUser. New C routine Tcl_AttemptCreateHashEntry. New C routines Tcl_ListObjRange, Tcl_ListObjRepeat, Tcl_ListObjReverse.
New C time API using long long in
New C time API using long long in place of Tcl_Time Case-insensitive filesystem paths on macOS. auto_execok and exec search reform on Windows. Revised searches for script library and encodings. Improved list internals for memory efficiency of large lists. Extended support for 64-bit sizes. Accessibility screen reader support. Initial support for bidirectional text / RTL languages. New widget ttk::toggleswitch. New command tk attribtable. send command revised and improved on Aqua. Handling of negative screen distances. Extended states in ttk::treeview and ttk::notebook Improvements to Tk_CanvasTextInfo Limit message box and dialogs to physical screen width. Improved listbox selection colors. Removed obsolete support for Windows XP appearances.