INT 61 - PCIBM PC/TCP(Transmission Control Protocol) A higher level (session layer) of the TCP/IP protocol suite.  See also IP, TCP/IP. kernel v2.05+ - "set_option" - SET AN OPTION ON A DESCRIPTOR
	AH = 20h
	BX = network descriptor
	CX = length of buffer (usually 04h)
	DS:DX -> buffer containing option
	SI = (ignored by v2.2-)
	DI = option to set (see #03468)
Return: CF clear if successful
	CF set on error
	    AX = error code (see #03319 at INT 61"FTP(File Transfer Protocol)  The standard protocol for copying files from one machine to another on a TCP/IP (Internet) network.  Also the program of the same name with which a user may transfer files. Software")
Notes:	Beame&Whiteside's BWPCTCP shim only supports options 01h and 0Bh; all
	  others return CF clear
	v2.11 reportedly stores the actual 32-bit value of an option in DS:DX
	  rather than using a buffer in memory
SeeAlso: INT 61"FTP(File Transfer Protocol)  The standard protocol for copying files from one machine to another on a TCP/IP (Internet) network.  Also the program of the same name with which a user may transfer files. Software",INT 61/AH=00h"PCIBM PC/TCP(Transmission Control Protocol) A higher level (session layer) of the TCP/IP protocol suite.  See also IP, TCP/IP.",INT 61/AH=21h


(Table 03468)
Values for PCIBM PC/TCP(Transmission Control Protocol) A higher level (session layer) of the TCP/IP protocol suite.  See also IP, TCP/IP. option to get or set:
 01h	set non-blocking mode if non-zero
 02h	timeout of call in milliseconds
 03h	user-defined 4-byte magic cookie (not used by kernel)
 04h	TCP(Transmission Control Protocol) A higher level (session layer) of the TCP/IP protocol suite.  See also IP, TCP/IP. window or UDP buffer count (WORD, unsigned)
 06h	do TCP(Transmission Control Protocol) A higher level (session layer) of the TCP/IP protocol suite.  See also IP, TCP/IP. keep-alives if non-zero
 09h	(v2.1+) set IP(Internet Protocol) The lower level (transport layer) of the TCP/IP protocol suite.	See also TCP, TCP/IP. precedence
 0Ah	(v2.1+) set IP(Internet Protocol) The lower level (transport layer) of the TCP/IP protocol suite.	See also TCP, TCP/IP. type of service
 0Bh	use a privileged port if port = 0
 0Ch	turn off TCP(Transmission Control Protocol) A higher level (session layer) of the TCP/IP protocol suite.  See also IP, TCP/IP. PUSH bit and don't flush buffer every write (see AH=1Ah)
Note:	use "C" true or false values for boolean options