Definition: integer i = sign(atom a)
Description: returns -1, 0, or +1 if a is negative, zero, or positive respectively.
Comments: sign(a) returns the same result as compare(a,0).

This function may be applied to an atom or sq_sign() to all elements of a sequence. The rules for sequence operations apply.
r = sign(5)         -- r is 1
r = sign(0)         -- r is 0
r = sign(-2.5)      -- r is -1
Implementation: See builtins\pmaths.e (an autoinclude) for details of the actual implementation.
See Also: compare