udp问题

我用api函数做了一个udp的socket,但是只能发包，不能收包。
初始化和收包如下：
int IntSocket()
{
sockaddr_in m_addr;
int nAddrLen,iReturnCode;

nAddrLen = sizeof(sockaddr_in);
memset(&m_addr, 0, sizeof(m_addr));
m_addr.sin_family = AF_INET;
m_addr.sin_port = htons(7123);
m_addr.sin_addr.s_addr = htonl(INADDR_ANY);

glSocket = socket(AF_INET, SOCK_DGRAM, 0);
if(glSocket<0)
iReturnCode = -1;
else
{
if(bind(glSocket,(struct sockaddr*)&m_addr, nAddrLen)! =0)
iReturnCode = -1;
else
iReturnCode = 0;
}

return iReturnCode;

}

iReturnCode = recvfrom(glSocket, cRecvBuf, sizeof(cRecvBuf), 0, (struct sockaddr *)&SourceAddr, &m_AddrLen);
if(iReturnCode>0)
{
sprintf(cMessage, "数据包长度%d ip[%s]port[%d]!", iReturnCode, inet_ntoa(SourceAddr.sin_addr),
ntohs(SourceAddr.sin_port));
AddtoView(cMessage, DISP_LEFT);
}
else
{
sprintf(cMessage, "数据包长度%d ip[%s] port[%d]!", iReturnCode, inet_ntoa(SourceAddr.sin_addr),
ntohs(SourceAddr.sin_port));
AddtoView(cMessage, DISP_LEFT);

}