Tcl_CancelEval, Tcl_Canceled - cancel Tcl scripts
Tcl_CancelEval(interp, resultObjPtr, clientData, flags)
- Tcl_Interp *interp (in)
- Interpreter in which to cancel the script.
- Tcl_Obj *resultObjPtr (in)
- Error message to use in the cancellation, or NULL to use a default
message. If not NULL, this object will have its reference count
decremented before Tcl_CancelEval returns.
- int flags (in)
- ORed combination of flag bits that specify additional options. For
Tcl_CancelEval, only TCL_CANCEL_UNWIND is currently
supported. For Tcl_Canceled, only TCL_LEAVE_ERR_MSG and
TCL_CANCEL_UNWIND are currently supported.
- ClientData clientData (in)
- Currently reserved for future use. It should be set to NULL.
Tcl_CancelEval cancels or unwinds the script in progress soon after the
next invocation of asynchronous handlers, causing TCL_ERROR to be the
return code for that script. This function is thread-safe and may be called
from any thread in the process.
Tcl_Canceled checks if the script in progress has been
canceled and returns TCL_ERROR if it has. Otherwise, TCL_OK is
returned. Extensions can use this function to check to see if they should
abort a long running command. This function is thread sensitive and may only
be called from the thread the interpreter was created in.
Any ORed combination of the following values may be used for the flags
argument to procedures such as Tcl_CancelEval:
- This flag is used by Tcl_CancelEval and Tcl_Canceled. For
Tcl_CancelEval, if this flag is set, the script in progress is
canceled and the evaluation stack for the interpreter is unwound. For
Tcl_Canceled, if this flag is set, the script in progress is
considered to be canceled only if the evaluation stack for the interpreter
is being unwound.
- This flag is only used by Tcl_Canceled; it is ignored by other
procedures. If an error is returned and this bit is set in flags,
then an error message will be left in the interpreter's result, where it
can be retrieved with Tcl_GetObjResult or
Tcl_GetStringResult. If this flag bit is not set then no error
message is left and the interpreter's result will not be modified.
interp(3tcl), Tcl_Eval(3tcl), TIP 285