5 * Code often wants to set a signal handler to clean up temporary files or
6 * other work-in-progress when we die unexpectedly. For multiple pieces of
7 * code to do this without conflicting, each piece of code must remember
8 * the old value of the handler and restore it either when:
10 * 1. The work-in-progress is finished, and the handler is no longer
11 * necessary. The handler should revert to the original behavior
12 * (either another handler, SIG_DFL, or SIG_IGN).
14 * 2. The signal is received. We should then do our cleanup, then chain
15 * to the next handler (or die if it is SIG_DFL).
17 * Sigchain is a tiny library for keeping a stack of handlers. Your handler
18 * and installation code should look something like:
20 * ------------------------------------------
21 * void clean_foo_on_signal(int sig)
30 * sigchain_push_common(clean_foo_on_signal);
34 * ------------------------------------------
39 * Handlers are given the typedef of sigchain_fun. This is the same type
40 * that is given to signal() or sigaction(). It is perfectly reasonable to
41 * push SIG_DFL or SIG_IGN onto the stack.
43 typedef void (*sigchain_fun
)(int);
45 /* You can sigchain_push and sigchain_pop individual signals. */
46 int sigchain_push(int sig
, sigchain_fun f
);
47 int sigchain_pop(int sig
);
50 * push the handler onto the stack for the common signals:
51 * SIGINT, SIGHUP, SIGTERM, SIGQUIT and SIGPIPE.
53 void sigchain_push_common(sigchain_fun f
);
55 void sigchain_pop_common(void);
57 #endif /* SIGCHAIN_H */