note: use "\r\n" for new line in szData string.
note: if is block when send content, it will be block
Parameters:
szServerIp - ip address of mail server
szFromAddr - from address
szHRecvAddr - to address
szSubject - mail subject
szData - mail data
szErrorMsg - variable to save error message
iErrorMsgLen - size of szErrorMsg
Returns:
if success, return 0.
if protocol error is occured, return -1.
if sending or receiving error is occured, return -2.
if can not create socket, return -3.
if input argument is not correct, return -10.