\u5176\u5be6\u7d00\u9304\u9019\u7bc7\u6587\u7ae0\uff0c\u6211\u672c\u8eab\u5c31\u6709\u9ede\u6015\u6015\u7684\uff0c\u6015\u6211\u628a\u7a0b\u5f0f\u7684\u932f\u8aa4\u89c0\u5ff5\u5e36\u7d66\u5176\u4ed6\u4eba<\/p>\n
\u8eab\u70ba\u5beb\u7a0b\u5f0f\u7684\u4eba\uff0c\u6211\u9664\u4e86\u5927\u5b78\u6709\u4fee\u904e\u7a0b\u5f0f\u8ab2\uff0c\u8cb7\u904e\u4e0a\u8ab2\u8981\u7528\u7684\u66f8\uff0c\u5c31\u518d\u4e5f\u6c92\u8cb7\u904e\u7a0b\u5f0f\u76f8\u95dc\u7684\u66f8\u7c4d<\/p>\n
\u9019\u4e09\u5e74\u4f86\uff0c\u5beb\u7a0b\u5f0f\u53ef\u4ee5\u8aaa\u90fd\u662f\u5f9e\u7db2\u8def\u4e0a\u770b\u904e\u5f88\u591a\u7684code\u81ea\u7fd2\u51fa\u4f86\u7684<\/p>\n
\u4f46\u5c31\u662f\u5982\u6b64\uff0c\u8b93\u6211\u767c\u73fe\u5728\u5beb\u65b0\u4e00\u4ee3\u8a9e\u8a00(Java\u3001Android\u3001C#)\u7684\u6642\u5019\uff0c\u7db2\u8def\u4e0a\u4e0d\u4e4f\u53c3\u8003\u7684\u6587\u7ae0<\/p>\n
\u800c\u9047\u5230C\/C++\u6216\u65e9\u671f\u7684WindowsMobile\u8cc7\u6599\u5c31\u986f\u5f97\u5f88\u5c11\uff0c\u751a\u81f3\u5e7e\u4e4e\u90fd\u8981\u5f9e\u5927\u9678\u90a3\u7bc7\u624d\u80fd\u5f97\u5230\u60f3\u8981\u7684\u8cc7\u8a0a<\/p>\n
\u79c9\u8457\u5403\u6c34\u679c\u62dc\u6a39\u982d\uff0c\u65e2\u7136\u6211\u662f\u5f9e\u7db2\u8def\u5b78\u5beb\u7a0b\u5f0f\uff0c\u6211\u4e5f\u5206\u4eab\u4e00\u4e9b\u6211\u7684\u7d93\u9a57\uff0c\u4f46\u4e5f\u8a31\u89c0\u5ff5\u6703\u6709\u932f\uff0c\u6240\u4ee5\u6709\u932f\u7684\u5730\u65b9\u9084\u8acb\u524d\u8f29\u5011\u6307\u6559\u3002<\/p>\n
<\/p>\n
\u6709\u6642\u5019Main Server\u53ef\u80fd\u6703\u639b\u6389\uff0c\u6240\u4ee5\u901a\u5e38\u6703\u6709\u4e00\u53f0Backup Server\uff0c\u5728Man Server\u9023\u7dda\u4e0d\u4e0a\u6642\uff0c\u53ef\u4ee5\u66f4\u63db\u6210\u9023\u7dda\u5230Backup Server<\/p>\n
\u4f46\u4e5f\u6709\u53ef\u80fd\u9023Backup Server\u4e5f\u6703\u639b\u9ede\uff0c\u6240\u4ee5\u7a0b\u5f0f\u6700\u597d\u80fd\u5728Main Server\u8207Backup Server\u4e92\u63db\uff0c\u5617\u8a66\u9023\u7dda\u4e00\u6bb5\u6642\u9593\u5f8c\uff0c\u518d\u767c\u51fa\u9023\u7ddaTimeOut<\/p>\n
\u4ee5\u4e0b\u7684\u7a0b\u5f0f\u78bc\u5c31\u662f\u9019\u500b\u7406\u5ff5\uff0c\u6211\u662f\u5728IBM\u7684AIX\u64b0\u5beb\u4ee5\u4e0b\u7a0b\u5f0f\uff1a<\/p>\n
[c]
\nbool isConnected = false;\/\/\u662f\u5426\u8207Server\u9023\u63a5\u4e0a
\nlong startTime = 0;\/\/\u7d00\u9304\u767c\u8d77\u9023\u7dda\u6642\u9593
\nint SockCount = 0;\/\/\u5617\u8a66\u9023\u7dda\u6b21\u6578
\nint ret = 0;
\nstruct timeval checktv;\t\/\/\u8a2d\u5b9a\u8f2a\u8a62timeout\u6642\u9593<\/p>\n
struct sockaddr_in SockAddr;
\nstruct in_addr TCPAddr;
\nint TCPPort;
\nTCPAddr.s_addr = inet_addr("192.168.1.100"); \/\/Main Server
\nTCPPort = atoi("1234");<\/p>\n
SockAddr.sin_family = AF_INET;
\nSockAddr.sin_port = TCPPort;
\nSockAddr.sin_addr = TCPAddr;<\/p>\n
checktv.tv_sec = 2;\/\/\u8f2a\u8a62\u6642\u95932\u79d2
\nchecktv.tv_usec = 0;
\nstartTime = ITime().asSeconds();\/\/\u7d00\u9304\u958b\u59cb\u9023\u7dda\u6642\u9593<\/p>\n
bSocket = socket(AF_INET, SOCK_STREAM, 0);<\/p>\n
while( isConnected )\/\/\u7121\u6cd5\u9023\u7ddareturn -1
\n{
\n\tfcntl(bSocket, F_SETFL, O_NONBLOCK);\/\/\u8a2d\u5b9aSocket\u6210non-blocking
\n\tret = connect( bSocket, ( struct sockaddr * )&SockAddr, sizeof( SockAddr ) );
\n\tfd_set writefds;
\n\tFD_ZERO( &writefds );
\n\tFD_SET( bSocket, &writefds );<\/p>\n
\tif(select( bSocket + 1, NULL, &writefds, NULL, &checktv ) <= 0)
\n\t{
\n\t\tSockCount++; \/\/\u5617\u8a66\u6b21\u6578+1
\n\t\tif(getSockCount == 5)\/\/\u5617\u8a66\u9023\u7dda\u5931\u6557\u4e94\u6b21\u5f8c\u63dbBackup Server
\n\t\t{
\n\t\t\tTCPAddr.s_addr = inet_addr("192.168.1.200");
\n\t\t\tTCPPort = atoi("1234");<\/p>\n
\t\t\tSockAddr.sin_family = AF_INET;
\n\t\t\tSockAddr.sin_port = TCPPort;
\n\t\t\tSockAddr.sin_addr = TCPAddr;<\/p>\n
\t\t\tbSocket = socket(AF_INET, SOCK_STREAM, 0);
\n\t\t}<\/p>\n
\t\tif(getSockCount == 10)\/\/\u518d\u5617\u8a66\u9023\u7dda\u5931\u6557\u4e94\u6b21\u53c8\u63db\u56deMain Server
\n\t\t{
\n\t\t\tTCPAddr.s_addr = inet_addr("192.168.1.100");
\n\t\t\tTCPPort = atoi("1234");<\/p>\n
\t\t\tSockAddr.sin_family = AF_INET;
\n\t\t\tSockAddr.sin_port = TCPPort;
\n\t\t\tSockAddr.sin_addr = TCPAddr;<\/p>\n
\t\t\tbSocket = socket(AF_INET, SOCK_STREAM, 0);
\n\t\t\tgetSockCount = 0;\/\/\u91cd\u8a2d\u8a08\u6578\u5668
\n\t\t}<\/p>\n
\t\tif( (ITime().asSeconds() – startTime) >= 40 )\/\/\u8a2d\u5b9a\u6700\u5927\u5617\u8a66\u9023\u7dda\u6642\u9593
\n\t\t{
\n\t\t\tclose( bSocket );
\n\t\t\tbreak;
\n\t\t}
\n\t\tcontinue;
\n\t}
\n\tisConnected = true;\/\/\u6210\u529f\u9023\u7d50\u5230Server
\n}
\n\u4ee5\u4e0b\u7701\u7565…….
\n[\/c]<\/p>\n
\u4ee5\u4e0a\u7a0b\u5f0f\u8981\u7279\u5225\u6ce8\u610f\u7684\u662f\uff0cconnect\u5c6c\u65bcblocking\u7684function\uff0c\u5728\u547c\u53eb\u5f8c\u5982\u679c\u6b32\u9023\u7d50\u7684Server\u9023\u4e0d\u4e0a
\n\u7a0b\u5f0f\u6703block\u4f4f\u4e00\u76f4\u7b49\u5f85Server\u56de\u61c9\uff0c\u5927\u7d0440~60\u79d2\u624d\u6703\u56de\u50b3-1\uff0c\u78ba\u5b9a\u9023\u7dda\u5931\u6557<\/p>\n
\u6240\u4ee5\u5982\u679c\u8981Main\u8207Backup Server\u5207\u63db\uff0c\u5c31\u9700\u628a\u9023\u7dda\u6539\u6210non-blocking\uff0c\u56e0\u6b64\u8981\u52a0\u5165fcntl(bSocket, F_SETFL, O_NONBLOCK)<\/p>\n
\u800c\u8981\u6ce8\u610f\u7684\u662f\uff0c\u5728Unix\u4e0a\u662ffcntl\uff0cioctlsocket\u662fWinSocket\u7684\u51fd\u5f0f\uff0c\u6211\u4e00\u958b\u59cb\u5c31\u50bb\u50bb\u7684\u547c\u53ebioctlsocket = =”<\/p>\n
\u53e6\u5916\u8981\u9054\u6210\u9019\u6a23\u7684\u6548\u679c\uff0c\u6700\u5927\u7684\u529f\u81e3\u975eselect\u83ab\u5c6c\u4e86\u3002\u90a3\u4ec0\u9ebc\u662fselect\u5462?<\/p>\n
\u4ed6\u53ef\u4ee5\u7528\u4f86\u5e6b\u4f60\u6aa2\u67e5\u4e00\u6574\u7d44(set)\u7684\u7269\u4ef6\u662f\u5426\u6709\u53ef\u4ee5\u8b80\u6216\u5beb\u7684\u8cc7\u6599\uff0c\u53ef\u7528\u5728IO\u7684\u8f2a\u8a62\u4e0a\u3002\u82e5\u5be6\u4f5c\u5728\u7db2\u8def\u4e0a\uff0c\u5c31\u53ef\u4ee5\u7528\u4f86\u6aa2\u67e5 socket \u662f\u5426\u5df2\u6210\u529f\u9023\u7dda\u3001\u63a5\u6536\u5230\u8cc7\u6599\u6216\u5c0d\u65b9\u662f\u5426\u5df2\u7d93\u95dc\u9589socket\u3002<\/p>\n
\u5b83\u7684\u51fd\u5f0f\u539f\u578b\u5982\u4e0b\uff1a
\n[c]
\nint PASCAL FAR select (
\n IN int nfds,
\n IN OUT fd_set FAR *readfds,
\n IN OUT fd_set FAR *writefds,
\n IN OUT fd_set FAR *exceptfds,
\n IN const struct timeval FAR *timeout);
\n[\/c]<\/p>\n
nfds \u8981\u88ab\u6aa2\u67e5\u7684 Sockets
\nreadfds \u6aa2\u67e5Sockets\u662f\u5426\u6709\u8cc7\u6599\u53ef\u8b80
\nwritefds \u6aa2\u67e5Sockets\u662f\u5426\u8cc7\u6599\u53ef\u5beb
\nexceptfds \u6aa2\u67e5Sockets\u662f\u5426\u932f\u8aa4
\ntimeout \u6aa2\u67e5Sockets\u7b49\u5f85\u7684\u6642\u9593<\/p>\n
\u6210\u529f\u7684\u8a71\u6703\u56de\u50b3\u7b26\u5408\u689d\u4ef6\u7684Socket\u7e3d\u6578\uff0c\u82e5Timeout\u767c\u751f\u6703\u56de\u50b30\uff0c\u5931\u6557\u7684\u8a71\u6703\u56de\u50b3-1\u3002(\u5728Windows\u7684\u74b0\u5883\u53ef\u4ee5\u900f\u904e\u547c\u53ebWSAGetLastError()\u5f97\u77e5SOCKET_ERROR\u539f\u56e0)<\/p>\n
\u518d\u4f86\uff0c\u7531\u65bc\u53c3\u6578readfds\u3001writefds\u8207exceptfds\u90fd\u662f\u50b3\u53c3\u8003\u547c\u53eb(called by reference)<\/p>\n
\u662f\u5c07\u53c3\u6578\u7684\u8a18\u61b6\u9ad4\u4f4d\u5740\u544a\u8a34select\u51fd\u5f0f\uff0c\u800cselect\u51fd\u5f0f\u5247\u6703\u5229\u7528\u9019\u4e9b\u503c\u4f86\u505a\u904b\u7b97\uff0c\u6700\u5f8c\u4e26\u5c07\u7d50\u679c\u518d\u5beb\u56de\u9019\u4e9b\u53c3\u6578\u7684\u4f4d\u5740\u4e2d<\/p>\n
\u6240\u4ee5\u9019\u4e9b\u53c3\u6578\u7684\u503c\u5728\u50b3\u5165\u524d\u548c\u51fd\u5f0f\u56de\u8fd4\u5f8c\uff0c\u53ef\u80fd\u6703\u4e0d\u540c\uff0c\u56e0\u6b64\u6bcf\u6b21\u547c\u53ebselect\u524d\uff0c\u5c0d\u9019\u4e9b\u53c3\u6578\u4e00\u5b9a\u8981\u91cd\u65b0\u8a2d\u5b9a\u5b83\u5011\u7684\u503c\u3002<\/p>\n
FD_ZERO(*set) \u6e05\u7a7a\u96c6\u5408(readfds\u3001writefds\u3001exceptfds)\u7684\u503c
\nFD_SET(s, *set) \u5c07Socket\u52a0\u5230\u96c6\u5408\u4e2d
\nFD_CLR(s, *set) \u5c07Socket\u5f9e\u96c6\u5408\u4e2d\u522a\u9664
\nFD_ISSET(s, *set) \u6aa2\u67e5Socket\u662f\u5426\u5b58\u5728\u65bc\u96c6\u5408\u4e2d<\/p>\n
select\u6700\u5f8c\u4e00\u500b\u53c3\u6578\u5c31\u662f\u8a2d\u5b9a\u6bcf\u6b21\u6aa2\u67e5\u7684timeout\u6642\u9593<\/p>\n
struct timeval checktv; \u5ba3\u544a\u6642\u9593\u7684\u7d50\u69cb
\nchecktv.tv_sec = 0;\u00a0\u00a0 \u00a0\u7b49\u5f85\u79d2\u6578
\nchecktv.tv_usec = 500000; \u7b49\u5f85\u5fae\u79d2\u6578\uff0c\u6ce8\u610f\u662f\u5fae\u79d2\u5594!!!
\n\u82e5\u5c07\u6b64\u7d50\u69cb\u653e\u5165select\u53c3\u6578\uff0c\u5247\u6703\u7b49\u5f85500\u6beb\u79d2\u624d\u6703\u767c\u751ftimeout\u8fd4\u56de\u3002<\/p>\n
\u53e6\u5916\u5982\u679c\u7528\u4f86\u505a\u8f2a\u8a62(polling)\uff0c\u5728Windows\u4e0a\u4f7f\u7528\u6642\u8981\u7279\u5225\u6ce8\u610f\uff0c\u82e5checktv.tv_sec\u8207checktv.tv_usec\u90fd\u8a2d\u7f6e\u70ba0\uff0c\u5c31\u5982\u540cwhile(1)\u7121\u7aae\u8ff4\u5708<\/p>\n
\u7531\u65bcUNIX\u7cfb\u7d71\u7684\u8a2d\u8a08\u8207Windows\u4e0d\u540c\uff0c\u5c6c\u65bcTims Sharing\u7684\u65b9\u5f0f\uff0c\u800c\u5728Windows\u7684\u7cfb\u7d71\u4e0a\u53ef\u80fd\u4e0d\u6703\u547c\u53eb\u5230Blocking Hook\u51fd\u5f0f\u4f86\u91cb\u653e\u63a7\u5236\u6b0a\uff0c\u9020\u6210\u7cfb\u7d71\u505c\u4f4f<\/p>\n
\u6700\u5f8c\u8981\u6ce8\u610f\u7684\u662f\uff0c\u547c\u53ebselect\u96c6\u5408\u8981\u653e\u5c0d\u53c3\u6578\uff0c\u8981\u505aconnect\u8f2a\u8a62\u8981\u653ewritefds\u53c3\u6578\u7684\u4f4d\u7f6e(\u7b2c\u4e09\u500b\u53c3\u6578)\uff0c\u8981\u505arecv\u63a5\u6536\u5c01\u5305\u6aa2\u67e5\u8981\u653ereadfds(\u7b2c\u4e8c\u500b\u53c3\u6578)\u3002<\/p>\n
\u653e\u932f\u4f4d\u7f6e\u6548\u679c\u53ef\u662f\u610f\u7fa9\u8207\u6548\u679c\u5b8c\u5168\u4e0d\u540c\uff0c\u9019\u4e5f\u662f\u6211\u767d\u75f4\u7684\u7d93\u9a57………….<\/p>\n","protected":false},"excerpt":{"rendered":"
\u5176\u5be6\u7d00\u9304\u9019\u7bc7\u6587\u7ae0\uff0c\u6211\u672c\u8eab\u5c31\u6709\u9ede\u6015\u6015\u7684\uff0c\u6015\u6211\u628a\u7a0b\u5f0f\u7684\u932f\u8aa4\u89c0\u5ff5\u5e36\u7d66\u5176\u4ed6\u4eba \u8eab\u70ba\u5beb\u7a0b\u5f0f\u7684\u4eba\uff0c\u6211\u9664\u4e86\u5927\u5b78\u6709\u4fee\u904e\u7a0b\u5f0f\u8ab2\uff0c…<\/span><\/p>\n