muduo总结

设置文件描述符为NonBlock和CloseOnExec

void setNonBlockAndCloseOnExec(int sockfd)
{
    // non-block
    int flags = ::fcntl(sockfd, F_GETFL, 0);
    flags |= O_NONBLOCK;
    int ret = ::fcntl(sockfd, F_SETFL, flags);

    // close-on-exec
    flags = ::fcntl(sockfd, F_GETFL, 0);
    flags |= FD_CLOEXEC;
    ret = ::fcntl(sockfd, F_SETFD, flags);

    (void)ret;
}

创建非阻塞且设置了close-on-exec套接字的两种方法

int sockfd = ::socket(AF_INET, SOCK_STREAM | SOCK_NONBLOCK | SOCK_CLOEXEC, IPPROTO_TCP);

int sockfd = ::socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
setNonBlockAndCloseOnExec(sockfd);

一般指定listen函数的第二个参数值为SOMAXCONN

::listen(sockfd, SOMAXCONN);

获取套接字发生的错误

int getSocketError(int sockfd)
{
    int optval;
    socklen_t optlen = static_cast<socklen_t>(sizeof optval);

    if (::getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval, &optlen) < 0)
    {
        return errno;
    }
    else
    {
        return optval;
    }
}

accept一个套接字并设置为non-block和close-on-exec的两种方法

sockaddr_in peeraddr;
bzero(&peeraddr, sizeof peeraddr);
socklen_t addrlen = static_cast<socklen_t>(sizeof peeraddr);
int connfd = ::accept(sockfd, (sockaddr*)&peeraddr, &addrlen);
setNonBlockAndCloseOnExec(connfd);

sockaddr_in peeraddr;
bzero(&peeraddr, sizeof peeraddr);
int connfd = ::accept4(sockfd, (sockaddr*)&peeraddr, &addrlen, SOCK_NONBLOCK | SOCK_CLOEXEC);