如何在C 語言中檢索本地電腦的IP 位址和子網路遮罩

確定本地電腦的IP 位址和子網路遮罩

#include 
#include 
#include 
#include 

int main() {
  struct ifaddrs *ifaddr;
  int err;
  if ((err = getifaddrs(&ifaddr)) != 0) {
    perror("getifaddrs");
    exit(EXIT_FAILURE);
  }
  for (struct ifaddrs *ifa = ifaddr; ifa != NULL; ifa = ifa->ifa_next) {
    if (!ifa->ifa_addr) continue;
    // Print the IP address
    if (ifa->ifa_addr->sa_family == AF_INET) {
      char ip[INET_ADDRSTRLEN];
      inet_ntop(AF_INET, &((struct sockaddr_in *)ifa->ifa_addr)->sin_addr, ip, INET_ADDRSTRLEN);
      printf("IP: %s\n", ip);
    }
    // Print the subnet mask
    if (ifa->ifa_netmask->sa_family == AF_INET) {
      char mask[INET_ADDRSTRLEN];
      inet_ntop(AF_INET, &((struct sockaddr_in *)ifa->ifa_netmask)->sin_addr, mask, INET_ADDRSTRLEN);
      printf("Subnet Mask: %s\n", mask);
    }
  }
  freeifaddrs(ifaddr);
  return 0;
}