namespace std {using sig_atomic_t =see below;
/ [support.signal], signal handlersextern"C"usingsignal-handler=void(int); / exposition onlysignal-handler* signal(int sig, signal-handler* func);
int raise(int sig);
}#define SIG_DFL see below#define SIG_ERR see below#define SIG_IGN see below#define SIGABRT see below#define SIGFPE see below#define SIGILL see below#define SIGINT see below#define SIGSEGV see below#define SIGTERM see below