Defining A Function Pointer Using Assignment In c

Question

I'm learning C. I know what the first line is doing; it's making a pointer to a function with no arguments and it returns an int. But wtf is the second doing?

My guess is that it is casting an int into a function? But what does it mean to turn an int into a function? Also, why does it cause an error when I try to call the function: 'function()'?

int (*function) ();
function = (int (*) ()) (1000);

Answer 1

Overall, the code is nonsense. Where did you get it from?

it's making a pointer to a function with no arguments

Rather, it is making a pointer to a function with obsolete style parameter list.

But wtf is the second doing?

It assigns the function pointer to point at address 1000 (decimal), my means of a cast from int to the function pointer type.

why does it cause an error when I try to call the function: 'function()'?

Likely because there is no such function allocated at address 1000. You might not even have access to that area etc.