int flags (in)                                      Flags governing the  trace  execution.
details of the calling sequence.
details on the calling sequence.
when the trace is deleted.
simultaneously for the same interpreter.
takes effect immediately, and the command is invoked with the new information.
the  state  of  the  interpreter, but run-time performance will be improved significantly.
then multiple calls to objProc will occur, one for each command.
The  parameters  to  the proc callback are similar to those of the objProc callback above.
Tcl_CreateTrace to abort execution of command.