x = optionaly returned numeric value if valid. i = test flag: 0: not a number. 1: txt is a long integer. 2: txt is a float. -1: first word of txt is a long integer. -2: first word of txt is a float.

$Id: isnumber.pro 142 2006-07-21 12:47:49Z navarro $

R. Sterner. 15 Oct, 1986. Johns Hopkins Applied Physics Lab. R. Sterner, 12 Mar, 1990 --- upgraded. Richard Garrett, 14 June, 1992 --- fixed bug in returned float value. R. Sterner, 1999 Nov 30 --- Fixed a bug found by Kristian Kjaer, Denmark Copyright (C) 1986, Johns Hopkins University/Applied Physics Laboratory This software may be used, copied, or redistributed as long as it is not sold and this copyright notice is reproduced on each copy made. This routine is provided as is without any express or implied warranties whatsoever. Other limitations apply as described in the file disclaimer.txt.