Inconsistency: "sort" on UNIX <-> Windows

[Daniel Luebbert <luebbert(at)stanford.edu>]

Hi,

I've been using the "sort" routine to sort an 2D-array by increasing
values of its first column.
The "sort" routine seems to behave differently in the UNIX and the
Windows versions of IDL5.3.

Here is a little test routine I wrote:

;**************************
pro test_sort
data = [[1,3], $
	[2,5], $
	[1,4], $
	[4,7], $
	[1,2] $
	]
		
print,"original: "
print,data
print,"sorted: "
print,data[*,sort(data[0,*])]
end
;**************************

The result on UNIX (Linux) is what I would expect:

;**************************
original: 

       1       3

       2       5

       1       4

       4       7

       1       2

sorted: 

       1       3

       1       4

       1       2

       2       5

       4       7

;**************************


BUT: The result on Windows is different:

;**************************
original: 
       1       3
       2       5
       1       4
       4       7
       1       2
sorted: 
       1       2
       1       4
       1       3
       2       5
       4       7
;**************************


In other words: The "sort" routine on Windows doesn't preserve the
original order of entries which have the same value (see the 3
"1"-values in my test data), but apparently rearranges them in a random
way.


What I'd like to know is:
How can it be that such a basic routine behaves differently in differnet
implementations of IDL?

And, more importantly: can anybody tell me how to make the
Windows-version of "sort" behave correctly,
without writing my own routine for sorting?

THanks for any hint,

Daniel


-- 
------------------------------------------------------------------------
 Dr. Daniel Lübbert
 Stanford Synchrotron Radiation Laboratory (SSRL)
 Bldg. 137, Mailstop 69, 2575 Sandhill Road, Menlo Park, CA 94025, USA
 Phone: (650) 926-4010 		FAX: (650) 926-4100 
 luebbert@slac.stanford.edu