what does NaN mean out of printf?

[flint at gistdev.UUCP]

NaN is not a number.  An easy way to get that is having a union, or by
doing a cast (of a long to a float) when you shouldn't.  For example, the
bit pattern for the integer -1L (all bits set) does not correspond to any
legal floating point value.  SYS V has an isnan(3C) function to test if a
value is legal floating point without generating an exeception. 

Flint Pellett, Global Information Systems Technology, Inc.
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