Qt Connect Signal Parent Slot

A developer can choose to connect to a signal by creating a function (a slot) and calling the connect function to relate the signal to the slot. Qt's signals and slots mechanism does not require classes to have knowledge of each other, which makes it much easier to develop highly reusable classes.

See below for answer
The QT widget contains a QGLWidget as in

Qt Signals And Slots Tutorial

Please try to accommodate types as I cannot copy paste to here. The Qt widget works fine and I can display data in the GL widget.
When some things in the GL widget change it is to notify the parent so a display can be updated. That GL widget looks like:

The best I can get is no compiler errors but a run time message:

No such slot QWidget::rcv_time_changed()

What code can be written such that a subordinate or enclosed widget can emit a signal to its enclosing widget?
I have also tried passing “this” to the subordinate, saving it as “sent_pointer” then directly calling a function with

That solicits the compile error:

Qt Signal Slot Example

Qt Connect Signal Parent Slot

Qt Connect Signal To Signal

Invalid use of incomplete type ‘class C_Strip_Chart’

Qt Connect Signal Slot

EDIT: ANSWER
For some reason, head-up-the-buttitis, I don't know, I concluded that signals and slots should be connected from the SIGNAL perspective, the sender. I finally tried doing the connect from the SLOT perspective and it worked right away. Now to delete all those multiple variations that are cluttering up my code. :-)