28 Apr
2020
28 Apr
'20
12:47 a.m.
On Mon, Apr 27, 2020 at 01:45:53PM -0400, Noel Chiappa wrote:
So I've been confused by this thread, and
I'm hoping someone can deconfuse me
- but I think I may have figured it out.
What's confusing me is that in C, the -> operator is followed by "an
identifier [which] designates a member of a structure or union object" (I
checked the spec to make sure my memory hadn't dropped any bits) - but g, h
above are arguments; so I couldn't figure out what was going on.
See below.
DF
#include <stdio.h>
struct h_ret { void (*i)(); };
struct g_ret { struct h_ret *(*h)(); };
struct f_ret { struct g_ret *(*g)(); };
void i_fn() { printf("I\n"); }
struct h_ret h_val = { i_fn };
struct h_ret *h_fn() { printf("H\n"); return &h_val; }
struct g_ret g_val = { h_fn };
struct g_ret *g_fn() { printf("G\n"); return &g_val; }
struct f_ret f_val = { g_fn };
struct f_ret *f_fn() { printf("F\n"); return &f_val; }
void fred(struct f_ret *(*f)())
{
#if 1
(*(*(*(*f)()->g)()->h)()->i)();
#else
f()->g()->h()->i();
#endif
}
int main() { fred(f_fn); return 0; }