为什么pcap_next_ex在Window上不断返回0

我使用winpcap来实现嗅探器，我一直在轮询下面的readpacket函数，但随机地（有时在1分钟后，有时在5小时后）我的程序在这个过程中被卡住了，因为rc一直等于0。为什么会发生这种情况？我错过了什么？

相关配置：

    pcap_set_snaplen (_pPCapHandle, 65535);
    pcap_set_promisc (_pPCapHandle, 1);
    pcap_set_timeout (_pPCapHandle, msPacketValid); //msPacketValid = 0
int PCapInterface::readPacket (uint8 *pui8Buf, uint16 ui16BufSize)
{
    struct pcap_pkthdr *pPacketHeader;
    const u_char *pPacketData;
    while (true) {
        int rc = pcap_next_ex (_pPCapHandle, &pPacketHeader, &pPacketData);
        if (rc > 0) {
            uint32 ui32PacketSize = ui16BufSize < pPacketHeader->caplen ? ui16BufSize : pPacketHeader->caplen;
            memcpy (pui8Buf, pPacketData, ui32PacketSize);
            return ui32PacketSize;
        }
        else if (rc == 0) {
            printf("read rc = 0...n");
            if (_bIsTerminationRequested) {
                return 0;
            }
        }
        else if (rc < 0) 
        {
            checkAndLogMsg ("PCapInterface::readPacket", Logger::L_MildError, "pcap_next_ex() returned %dn", rc);
            return -1;
        }
    }
}