bsdsignal.c

非常流行而且必须的网络功能

/*
 * bsdsignal.c
 *
 * Use sigaction() to simulate BSD signal()
 */

#include <signal.h>
#include <stdlib.h>
#include <string.h>

void (*bsd_signal(int, void (*)(int)))(int);

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;
}