/* * bsdsignal.c * * Use sigaction() to simulate BSD signal() */#include "config.h"void (*bsd_signal(int signum, void (*handler)(int)))(int){  struct sigaction action, oldaction;  memset(&action, 0, sizeof action);  action.sa_handler = handler;  sigemptyset(&action.sa_mask);  sigaddset(&action.sa_mask, signum);  action.sa_flags = SA_RESTART;    if (sigaction(signum, &action, &oldaction) == -1) {#ifdef SIG_ERR    return SIG_ERR;#else    return NULL;#endif  }  return oldaction.sa_handler;}