#include <string.h>#include <signal.h>/* Global variable */sigset_t _sigintr;              /* Set by siginterrupt.  */__sighandler_t__signal (int sig, __sighandler_t handler, int flags){  int ret;  struct sigaction action, oaction;  memset(&action, 0, sizeof(struct sigaction));  action.sa_handler = handler;  action.sa_flags = flags;  ret = sigaction (sig, &action, &oaction);   return (ret == -1) ? SIG_ERR : oaction.sa_handler;}__sighandler_tsignal (int sig, __sighandler_t handler){  return __signal(sig, handler, (SA_ONESHOT | SA_NOMASK | SA_INTERRUPT) & ~SA_RESTART);}