Non-blocking connect i Linux

Jeg har følgende funktion til at connecte en socket uden at blokere som almindelige connect:

int do_connect(int fd, struct sockaddr *remote, socklen_t len, int *err)
{
    struct timeval timeout;
    int saveflags,ret,back_err;
    fd_set fd_w;

    int on = 1, off = 0;

    timeout.tv_sec = 3;
    timeout.tv_usec = 0;
if (ioctl(fd, FIONBIO, &on) < 0)
    {
        perror(\"ioctl1\\n\");
        *err = errno;
        return -1;
    }

    /* This will return immediately */
    *err=connect(fd,remote,len);
    back_err=errno;

if (ioctl(fd, FIONBIO, &off) < 0)
    {
        perror(\"ioctl2\\n\");
        *err = errno;
        return -1;
    }

    /* return unless the connection was successful or the connect is still in progress. */
    if(*err<0 && back_err!=EINPROGRESS)
    {
        perror(\"connect\\n\");
        *err=errno;
        return -1;
    }

    FD_ZERO(&fd_w);
    FD_SET(fd,&fd_w);

    *err=select(fd+1, NULL, &fd_w,NULL, &timeout);

    if(*err<0)
    {
        perror(\"select\\n\");
        *err=errno;
        return -1;
    }

    /* 0 means it timeout out & no fds changed */
    if(*err==0)
    {
        close(fd);
        *err=ETIMEDOUT;
        return -1;
    }

    /* Get the return code from the connect */
    len=sizeof(ret);
    *err=getsockopt(fd,SOL_SOCKET,SO_ERROR,&ret,&len);
    if(*err<0)
    {
        perror(\"getsockopt\\n\");
        *err=errno;
        return -1;
    }

    /* ret=0 means success, otherwise it contains the errno */
    if(ret)
    {
        *err=ret;
        return -1;
    }
    *err=0;
    return 0;
}

Problemet er at den blokerer alligevel.
Hvor har jeg lavet en fejl?