Pointer as function argumnet

[NKP]

Hi,
I have a code snippet:

#include<stdio.h>
int fun(int(*) ());
int main()
{
fun(main);
printf("Hi\n");
return 0;
}

int fun(int (*p) ())
{
printf("Hello");
return 0;
}

The output is
Hello Hi

Not clear what happens when fun(main) is invoked and why?
Can anyone clarify?

[tabstop]

You are passing an object of type

int(*) ()

to the function; i.e., a function returning int and taking unknown arguments. In your function, it is called p.

Then when you get to the function, you completely ignore it and do a printf. return returns from the function back to whence it came.

[MK27]

a function returning int and taking unknown arguments. In your function, it is called p.
Then when you get to the function, you completely ignore it

To really understand this you might want to try adding the following couple lines:

int fun(int (*p) ())
{
int x;
printf("Hello");
x = p();
return 0;
}

[DeadPlanet]

lol, and cause some sort of stack overflow?

[MK27]

lol, and cause some sort of stack overflow?

Takes a hundred thousand iterations or so.

Hello130833 Hello130834 Hello130835 Hello130836 Hello130837 Hello130838 Hello130839 Hello130840 Hello130841 Hello130842 Hello130843 Hello130844 Hello130845 Hello130846 Hello130847 Hello130848 Hello130849 Hello130850 Hello130851 Hello130852 Hello130853 Hello130854 Hello130855 Hello130856 Hello130857 Hello130858 HeSegmentation fault

Clearly this is the helium variety fault.