Re: blocking socket is nonblocking after calling gnulib select() in windows

[Bastien ROUCARIES]

> Is the gnulib select() only intended to be used with nonblocking sockets on
> windows?

I have just tested the program at the end of the file, it thread is
blocked when enable =0 (block socket) and enable=1 it fail with
WSAEWOULDBLOCK

So i possible stragegy will be:
1. createathread TID from parent
2. in TID do WSAIoctl(sock, SIO_ADDRESS_LIST_CHANGE,NULL, 0, NULL,
0,&bytes,NULL,NULL);
3. in  parent: if TID returned with WSAEWOULDBLOCK tag socket non blocking
4. query running state of TID, if suspended socket is blocking, kill
thread and mark socket blocking

I have no time to implement and it will need some caching but it will
allow to retrieve block/non block status of socket.

Bruno I think you could try to code this kind of stuff; I lack time
for a few weeks

Bastien





#include "winsock2.h"
#include <iostream>
#include <cstdio>
using namespace std;



void wsock_init();

int main() {
    int rc;
    wsock_init();
    DWORD bytes;
    SOCKET sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    struct sockaddr_in si;
    si.sin_family = AF_INET;
    si.sin_port = htons(80);
    si.sin_addr = *(struct in_addr*)gethostbyname("www.google.com")->h_addr;
    memset(&(si.sin_zero), 0, 8);

    if (connect(sock, (struct sockaddr*)&si, sizeof(struct sockaddr))) {
        cout << "Could not connect to host.\n";
        return 1;
    }

    cout << "before\n";
    u_long enable = 1;
    ioctlsocket(sock,FIONBIO, &enable);
    std::cout << "block done\n";
    std::cin.get();
    rc = WSAIoctl(sock, SIO_ADDRESS_LIST_CHANGE,NULL, 0, NULL,
0,&bytes,NULL,NULL);
    if (rc == SOCKET_ERROR)
    {
      if (WSAGetLastError() != WSA_IO_PENDING)
      {
          fprintf(stderr, "WSAIoctl: SIO_ADDRESS_LIST_CHANGE failed:
%d\n", WSAGetLastError());
          std::cin.get();
          return -1;
       }
    }
    cout << "after";



    shutdown(sock, SD_BOTH);
    closesocket(sock);
    WSACleanup();

    std::cin.get();
    return 0;
}

void wsock_init() {
    WSADATA wd;
    if (WSAStartup(MAKEWORD(1, 1), &wd)) {
        cout << "Error initializing Winsock DLL" << endl;
        exit(1);
    }
}