Usage of the "C" keyword void

There are two functions of void

"1" No

"2" any type

There will be different interpretations of where void appears.

"1" void func (void)

Func to the left of void, which means "no return value"

The void in parentheses to the right of the Func represents the function "no arguments"

"2" int func (void *a), modifier pointer variable (more commonly used for function arguments)

Indicates that parameter a can be any type of pointer variable

"3" #define NULL ((void*) 0), modifier constants (typically defined with macro)

Here null is numerically 0, but in this case, you can indicate that NULL is an (arbitrary) pointer type data

Usage of the "C" keyword void