Experimental Physics and
Industrial Control System

"Peregrine M. McGehee" <[email protected]> · Fri, 19 Apr 2002 15:14:30 -0600

In the simple drvNode framing routines I alluded to earlier
we allowed a set of multiple terminators. On a character by
character basis the index into each terminator was incremented until
either a mismatch occurred or a complete terminator was found. 
While in our application we defined the terminators at the vxWorks command
line, modifying the drvAscii <readCmt> construct would be
straightforward.

drvNode usage is:
 * A delimiter definition includes:
 *     n     - index into delimiter array [0..NDELIMITERS-1]
 *     len   - length of delimiter in characters. (0 = delimiter not defined)
 *     delim - delimiter string
 *     mask  - bit mask indicating which positions are wild carded.
 * Examples:
 *     drvNodeSetDelim(COMMON, 2, 2, "\015\012", 0x00)
 *          delimiter #2 = CRLF
 *     drvNodeSetDelim(MOUSE, 0, 3, "   ", 0x07)
 *	    delimiter #0 = any sequence of three characters (useful
 *          for mouse pointing devices).       

By adding two optional syntax elements to the drvAscii <readCmt> 
links this could be emulated, i.e.
	o add an optional delimiter number (default=0)
	o allow a %k construct within the terminator string
	(default = not used).
So the examples above could be written as:
 	field(OUT,"@COMMON <readCmt 2 %s>")
	field(VAL,"\015\012")
and
	field(OUT,"@MOUSE <readCmt %s>")
	field(VAL,"%3k").

Note that drvNode returns the terminator string. 

- Peregrine     
-- 
Peregrine M. McGehee	[email protected]	(505) 667-3273
Sloan Digital Sky Survey / Spallation Neutron Source
MS H820, Los Alamos National Laboratory, Los Alamos, NM 87545

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System