Bounty program for improvements to Tcl and certain Tcl packages.
Author:         Rene Meyer <>
State:          Final
Type:           Project
Vote:           Done
Created:        21-Jul-2005
Tcl-Version:    8.5


Currently only a limited set of types of C variable may be linked to using Tcl_LinkVar. This TIP proposes extending this to cover all the basic numeric C types.


With the current implementation it is not possible to link the following types directly to a Tcl variable, making it much more difficult to couple such variables to the Tcl level (compared with int or double variables). This TIP fixes this, making it easier to link C variables and embedded Tcl code.

  • char

  • unsigned char

  • short

  • unsigned short

  • unsigned int

  • long

  • unsigned long

  • Tcl_WideUInt

  • float

There will be no impact on current applications.


The new types are inserted as new #define TCL_LINK_* statements in the tcl.h header file and in the switch statements in the Tcl_Link functions.

The documentation of Tcl_*Link* should mention the new types.

Reference Implementation

A reference implementation is available as Patch #1242844 on SourceForge .


This document has been placed in the public domain.