# observe(n) 2.8 observe.n "TkCon"

## Name

observe - Runtime debugging output in TkCon

## Synopsis

- observe command cmdname ?maxlevel?
- observe cdelete cmdname
- observe cinfo cmdname
- observe variable varname operation ?args?
- observe vdelete varname operation
- observe vinfo varname

## Description

This command provides runtime debugging output for variables and commands without the need to edit your code. For variables, the underlying mechanism uses trace and dump var. For commands, it renames the observed procedure and uses a special wrapper procedure. WARNING: using this procedure after checkpointing state will result in major problems if you clean state because the renamed (true) commands will be lost.

This procedure is experimental. Comments are encouraged.

observe command cmdname ?maxlevel?

  This will create a wrapper command which prints out (using dump) the call stack to the console. maxlevel represents the maximum number of levels of the call stack which will be printed (defaults to 4).

observe cdelete cmdname

  Removes the wrapper around an observed command.

observe cinfo cmdname

  Prints out useless info.

observe variable varname operation ?args?

  Currently a wrapper around trace that uses dump to print out the value of the named variable whenever the specified operation on that variable occurs (must be read, write or unset).

observe vdelete varname operation

  Deletes the trace wrapper around the named variable.

observe vinfo varname

  Prints out trace info about the named variable.

## See Also

dump(n), idebug(n), tkcon(1), tkcon(n), tkconrc(5)

## Keywords

Tk, console, debug

## Copyright

Copyright © Jeffrey Hobbs <jeff at hobbs.org>