출처 :Advanced Programming in the UNIX® Environment: Second Edition
typedef void Sigfunc(int); /* for signal handlers */
static Sigfunc *_Signal(int signo, Sigfunc *func);
static Sigfunc *_Signal_Intr(int signo, Sigfunc *func);
/*
* Reliable version of signal(), using POSIX sigaction().
*/
static Sigfunc *_Signal(int signo, Sigfunc *func)
{
struct sigaction act, oact;
act.sa_handler = func;
sigemptyset(&act.sa_mask);
act.sa_flags = 0;
if (signo == SIGALRM) {
#ifdef SA_INTERRUPT
act.sa_flags |= SA_INTERRUPT;
#endif
}
else {
#ifdef SA_RESTART
act.sa_flags |= SA_RESTART;
#endif
}
if (sigaction(signo, &act, &oact) < 0) {
return(SIG_ERR);
}
return(oact.sa_handler);
}
/*
* a version of the signal function that tries to
* prevent any interrupted system calls from being restarted.
*/
static Sigfunc *_Signal_Intr(int signo, Sigfunc *func)
{
struct sigaction act, oact;
act.sa_handler = func;
sigemptyset(&act.sa_mask);
act.sa_flags = 0;
#ifdef SA_INTERRUPT
act.sa_flags |= SA_INTERRUPT;
#endif
if (sigaction(signo, &act, &oact) < 0) {
return(SIG_ERR);
}
return(oact.sa_handler);
}
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