1
我正在玩跨平臺框架中的套接字層,我試圖讓連接以非阻塞方式工作。然而,在翻閱文檔之後,他們似乎根本沒有正確的表現。問題的核心在於,在啓動非阻塞之後,請連接以下選擇失敗以注意連接已成功並一再重複超時。非阻塞連接上的MacOSX select()行爲不正確
SOCKET s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
hostent *h = gethostbyname("www.memecode.com");
if (h)
{
sockaddr_in addr;
memset(&addr, 0, sizeof(addr));
addr.sin_family = AF_INET;
addr.sin_port = htons(80);
if (h->h_addr_list && h->h_addr_list[0])
{
memcpy(&addr.sin_addr, h->h_addr_list[0], sizeof(in_addr));
// Set non blocking
fcntl(s, F_SETFL, O_NONBLOCK);
int64 start = LgiCurrentTime();
int status = connect(s, (sockaddr*) &addr, sizeof(sockaddr_in));
printf("Initial connect = %i\n", status);
while (status && (LgiCurrentTime()-start) < 15000)
{
// Do select to wait for connect to finish
fd_set wr;
FD_ZERO(&wr);
FD_SET(s, &wr);
int TimeoutMs = 1000;
struct timeval t = {TimeoutMs/1000, (TimeoutMs % 1000) * 1000};
errno = 0;
int64 sel_start = LgiCurrentTime();
int ret = select(0, 0, &wr, 0, &t);
int64 sel_end = LgiCurrentTime();
printf("%i = select(0,%i,0) errno=%i time=%i\n",
ret,
FD_ISSET(s, &wr)!=0,
errno,
(int)(sel_end-sel_start));
if (ret > 0 && FD_ISSET(s, &wr))
{
// ready for connect to finish...
status = connect(s, (sockaddr*) &addr, sizeof(sockaddr_in));
printf("2nd connect = %i\n", status);
if (status)
{
if (errno == EISCONN)
{
status = 0;
printf("error = EISCONN so we're good.\n");
}
}
}
// else still waiting...
}
}
else printf("host addr error.\n");
}
else printf("gethostbyname failed.\n");
當我運行MacOSX上的最新豹構建這個代碼我得到這樣的輸出:
Initial connect = -1
0 = select(0,1,0) errno=0 time=1000
0 = select(0,1,0) errno=0 time=1000
0 = select(0,1,0) errno=0 time=1000
0 = select(0,1,0) errno=0 time=1000
0 = select(0,1,0) errno=0 time=1000
0 = select(0,1,0) errno=0 time=1000
0 = select(0,1,0) errno=0 time=1000
0 = select(0,1,0) errno=0 time=1000
0 = select(0,1,0) errno=0 time=1000
0 = select(0,1,0) errno=0 time=1001
0 = select(0,1,0) errno=0 time=1000
0 = select(0,1,0) errno=0 time=1000
0 = select(0,1,0) errno=0 time=1000
0 = select(0,1,0) errno=0 time=1000
0 = select(0,1,0) errno=0 time=1000
當我經過選擇刪除「RET> 0」的情況下連接成功並返回EISCONN。所以連接在幕後工作,但選擇從不接受。根據我對選擇返回值的理解,它包含fd_set結構中的套接字數量,如果沒有事件發生,則返回0。
我的代碼有什麼問題?
PS LgiCurrentTime()從某點開始返回毫秒,例如, GetTickCount在Windows上......我忘記了Mac上的確切實施,但它並不重要......只是計時信息。
咦......那好吧......最快的答案永遠!我是來自窗戶的難民,在那個平臺上,第一個參數完全被忽略。 Thx快速回復。 – fret 2009-08-08 22:27:26
Ha;)在這個問題中看到「meme」也很有趣。我的公司名爲Memention - http://memention.com – epatel 2009-08-08 22:31:32