This REXX extension DLL returns the system's free memory, either physical 
or virtual.  The returned string will be an integer from 524288 to 
4294967295. 

For whatever reason, OS/2 doesn't return less than 512K free memory 
(perhaps it actually keeps that much free as a buffer).

To use, put this in your REXX script:

call RxFuncAdd 'RxFreeMem','RxFMem','RxFreeMem'

You may then call RxFreeMem().

The function takes either one argument, or no argument.  

The valid arguments are 'Virtual' and 'Physical', case-insensitive.  The 
first letter alone is also sufficient.

The default if no argument is given is to return physical memory.

Examples:

say 'Physical memory free: '||RxFreeMem()
say 'Virtual memory free: '||RxFreeMem('v')
say 'Physical memory free: '||RxFreeMem('Physical')

Non-valid arguments will cause a syntax error.

Free physical memory is determined by the Dos16MemAvail() API call (which 
is undocumented, and not declared in VACPP's headers, strangely enough).

Free virtual memory is determined by a DosQuerySysInfo() API call, using 
the QSV_TOTAVAILMEM identifier.

The source and module definition file are in the source.zip archive.
