The Jim Interpreter

Thursday, 16 July 2026

Jim Tcl version 0.84

ANNOUNCE: Jim Tcl version 0.84

Jim Tcl 0.84 has been released and is available from:

https://github.com/msteveb/jimtcl

Find out all about Jim Tcl at http://msteveb.github.io/jimtcl/

CHANGES SINCE VERSION 0.83

This release contains bug fixes, documentation improvements, and several important fixes for correctness and safety. A summary is below. See git for the full changelog.

Thanks to everyone who contributed to this release.

Bugs fixed in version 0.84

• fix uninitialized upvar when binding procedures
• fix out-of-bounds read in string first
• fix unchecked truncation in SetIndexFromAny
• [wait -nohang] now returns correct result when child still running
• exec fall-back implementation compilation issues fixed
• regsub now properly handles usage errors (returns code -1)
• regsub -all no longer loops forever when matching everywhere
• try error handling now properly handles shorter errorCode
• abort on boolean negation/plus unary operators fixed
• aio write on EPIPE now properly discards write buffer
• dict set/unset now ensures dicts modified via dict sugar are unshared
• Jim_SetVariable() now properly frees value on error

Features and improvements added in version 0.84

• Major features:
  • TIP 424 support: new safer exec | syntax and open "|| pipeline..." support
  • Optional taint support for improved data security

  • aio now supports translation mode (binary

    text) and configurable buffering

  • lsubst command to create lists using subst-style substitution
  • package forget command support
  • Jim_RegisterCommand() API for improved C command registration with arg checking
  • info usage returns usage for procs and native commands
  • info aliases lists all aliases
• Regex improvements:
  • regexp and regsub now support -expanded flag
  • regexp and regsub now support -lineanchor and -linestop flags
  • regexp now properly handles non-repeat count {...}
  • regexp -all now properly assigns match variables
• Expression improvements:
  • expr now supports =* (string glob match) and =~ (string regex match) operators
  • ./configure --compat now properly enables expr with multiple args
• Documentation:
  • Extensive public API documentation added
  • subst with $(...) documented
• Other improvements:
  • parray now allows additional arguments per Tcl compatibility
  • vwait now accepts script argument
  • regexp and regsub now sort -- after other options for Tcl 9.0 compatibility
  • info patchlevel now returns git version if available
  • Jim_EvalFile now accepts input from any readable file
  • linenoise updated with grapheme cluster support for better Unicode handling
  • tcltest improved to support any Tcl version >= 8.5
  • os.umask command added
  • MorphOS platform support added
  • jimsh improved stdin/tty handling
  • Improve Jim_Stack API and remove unused ABI fields
  • Improved build compatibility with updated autosetup to v0.7.2+

Possible incompatibilities in version 0.84

• Jim_RegisterCommand() API changes for C extensions using direct command registration
• If taint checking is enabled (.i.e. not disabled with –disable-taint) it may block certain operations that otherwise would have been allowed. See README.taint.
• Jim_SetVariable() now frees the value on error so callers should not attempt to do so

Steve Bennett (steveb@workware.net.au)