#include <csignal>
  void ( *signal( int signal, void (* func) (int)) ) (int);

The signal() function sets func to be called when signal is recieved by your program. func can be a custom signal handler, or one of these macros (defined in the csignal header file):

Macro Explanation
SIG_DFL default signal handling
SIG_IGN ignore the signal

Some basic signals that you can attach a signal handler to are:

Signal Description
SIGTERM Generic stop signal that can be caught.
SIGINT Interrupt program, normally ctrl-c.
SIGQUIT Interrupt program, similar to SIGINT.
SIGKILL Stops the program. Cannot be caught.
SIGHUP Reports a disconnected terminal.

The return value of signal() is the address of the previously defined function for this signal, or SIG_ERR is there is an error.