Assignment for structures – PB Docs 2019

Declaring a structure variable creates an instance of that
structure:

When you assign a structure to another structure, the whole
structure is copied and a second copy of the structure data
exists:

The assignment copies the whole structure from one structure
variable to the other. Each variable is a separate instance of the
structure str_emp_data.

Restriction on assignment

If the structures have different definitions, you cannot assign
one to another, even if they have the same set of variable
definitions.

For example, this assignment is not allowed:

For information about passing structures as function arguments,
see Passing arguments to
functions and events.