Register a property of a child of the element to allow it to be written with set_child_property and read with get_child_property.
A change in the property will also appear in the deep_notify signal.
pspec should be unique from other children properties that have been registered on this.
| this | |
| pspec |
The specification for the property to add |
| child |
The Object who the property belongs to |
|
true if the property was successfully registered. |