10-4 SO_REUSEADDR を有効にしたTCP サーバ

#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>

int
main()
{
  int sock0;
  struct sockaddr_in addr;
  struct sockaddr_in client;
  socklen_t len;
  int sock;
  int yes = 1;

  sock0 = socket(AF_INET, SOCK_STREAM, 0);

  addr.sin_family = AF_INET;
  addr.sin_port = htons(12345);
  addr.sin_addr.s_addr = INADDR_ANY;

  setsockopt(sock0,
      SOL_SOCKET, SO_REUSEADDR, (const char *)&yes, sizeof(yes));

  bind(sock0, (struct sockaddr *)&addr, sizeof(addr));

  listen(sock0, 5);

  while (1) {
    len = sizeof(client);

    sock = accept(sock0, (struct sockaddr *)&client, &len);

    write(sock, "HELLO", 5);

    close(sock);
  }

  close(sock0);

  return 0;
}

拙著「Linuxネットワークプログラミング」の紹介