Why is it not enough to declare the structure alias when using the structure variable of other files in C language, and the proper name must be used? (cannot add struct when using alias)

problem

Pictured , I am here a Files use b The structure variable of the file , When declaring a structure , You have to use the real name of the structure

kyai.h

kyai.c

demo_main.c

Not by alias

reason

Alias cannot be added struct, Otherwise, it will report a mistake

It can be like this
demo_main.c

Be careful , When creating a structure , You can't add... When using aliases struct, Will report a mistake

kyai.c


That's all right

Reference article ： How to .c File declares another .c The structure defined in the file ？