How do I read this complex declaration in C? [duplicate]

Answer 1

Using cdecl.org, you get

declare signal as function (int, pointer to function (int) returning void) returning pointer to function (int) returning void

for the input

void (*signal(int, void(*)(int)))(int)

This means signal is a function. The result of of calling signal is pointer to a function void f(int).

Explanation: The signal() call installs a new signal handler and returns the old signal handler (so you can restore it later if you want to).