Example-PLI How use unsigned integers as arguments in PL/I

Copyright (c) Kednos Corporation 2008. All rights reserved
LAYERED PRODUCT:  Alpha PLI, V4.5          OP/SYS: VMS, V8.3
                  VAX   PLI, V3.8          OP/SYS  VMS, V7.3

SOURCE:     Kednos Customer Support Center


OVERVIEW:

Many system routines require areguments be unsigned 16 bit integers.  PL/I does
not have such a native data type, so here we present several techniques for 
accomplishing this


For 16 bit unsigned integers there are two methods the first doesn't require
additional storage and the second needs a fixed binary(31) for temporary
storage

1.      rab.rab$w_rsz = int(reverse(bit(bytesize(msg_block(blk))), 1, 16);
	In this example the size of the msg_block was greater than 32767
	which is the largest fixed binary(15) but less than 65536, the
	largest unsigned integer that fits into a 16-bit word.

2.	dcl temp fixed binary(31), 
	    alias fixed bin(15) based;
	temp = size(msg_block(blk)) - 65536;
	rab.rab$w_rsz = addr(temp) -> alias;

	N.B.  This presumes little endian byte ordering

3.	dcl temp fixed binary(31), 
	    alias fixed bin(15) based(addr(temp));
	temp = size(msg_block(blk)) - 65536;
	rab.rab$w_rsz = alias;