[str,ok]=tcpip_readln(fid,len)
fid is file id.
len is maximum length to be read.
Reads a line of charters terminated by newline character (LF).
If the a full line (until LF) isn available at the
moment a empty string will be returned.
CR and LF characters will not be returned in the string.
Returns ok set to 1 if a complete line whas recived.
Psychtoolbox/PsychHardware/iViewXToolbox/tcp_udp_ip/tcpip/tcpip_readln.m