One 、void Role of type

1.C In language ,void It is an uncertain type , Cannot be used to declare variables . Such as void a=10; It's wrong. .

2. It is often used to limit the return type of a function . Such as void fun(int a);

3. It is often used to limit function parameters . Such as int fun(void);

Two 、void* The pointer

1. Definition ：void* Is the pointer type with undetermined step size .

2. Generally used for function parameters 、 The return value of the function needs to be compatible with different pointer types .

3.void* Type variables can accept the assignment of pointers of any type , And there is no need to cast .void* Can be assigned to any type of variable , But you need to cast the result to make sense .

Such as

void* a=NULL;
int* b=NULL;
a=b;

int*a=NULL;
void *b=NULL;
a=(int*)b;

Although no error was reported , But such assignment is meaningless , It's not reasonable .

void* Reference resources