阻塞模式的accept线程退出

在退出时，主线程依次调用 shutdown 和 closesocket 良好的关闭 accept  对应的 socket，此时 accept 工作线程中 accept 函数会返回 INVALID_SOCKET。

#include <winsock2.h>
#include <stdio.h>
#pragma comment(lib, "ws2_32.lib")

SOCKET listen_socket;

bool Init(unsigned short listen_port)
{
 SOCKADDR_IN local;
 listen_socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
 if (listen_socket == INVALID_SOCKET)
 {
  return false;
 }
 local.sin_addr.S_un.S_addr = htonl(INADDR_ANY);
 local.sin_family = AF_INET;
 local.sin_port = htons(listen_port);

 if (bind(listen_socket, (sockaddr *)&local, sizeof(SOCKADDR_IN)) == SOCKET_ERROR)
 {
  closesocket(listen_socket);
  listen_socket = INVALID_SOCKET;
  return false;
 }
 if (listen(listen_socket, 32) == SOCKET_ERROR)
 {
  closesocket(listen_socket);
  listen_socket = INVALID_SOCKET;
  return false;
 }
 return true;
}

DWORD WINAPI AcceptThreadProc(LPVOID param)
{
 while (!*(bool *)param)
 {
  sockaddr_in remote_addr;
  int addr_len = sizeof(sockaddr);
  printf("accept start\n");
  SOCKET sock = accept(listen_socket, (sockaddr *)&remote_addr, &addr_len);
  printf("socket = %d\n", sock);
 }
 return 0;
}

int main()
{
 WSADATA wsa_data;
 if (WSAStartup(MAKEWORD(2, 2), &wsa_data) != 0)
 {
  return 0;
 }
 if (Init(9999))
 {
  bool stop = false;
  HANDLE accept_thread = CreateThread(0, 0, AcceptThreadProc, &stop, 0, 0);
  if (accept_thread != NULL)
  {
   system("pause"); 
  }
  stop = true;
  shutdown(listen_socket, SD_BOTH);
  closesocket(listen_socket);
  WaitForSingleObject(accept_thread, INFINITE);
  CloseHandle(accept_thread);
  accept_thread = NULL;
 }
 WSACleanup();
 return 0;
}