erf(3M)                                                      erf(3M)


       NAME
             erf, erfc - error function and complementary error function

       SYNOPSIS
             cc [flag ...] file ...  -lm [library ...]
             #include <math.h>
             double erf(double x);
             double erfc(double x);

       DESCRIPTION
             erf returns the error function of x, defined as

             erfc, which returns 1.0 - erf(x), is provided because of the
             extreme loss of relative accuracy if erf(x) is called for
             large x and the result subtracted from 1.0 (for example, for x
             = 5, 12 places are lost).

          Errors
             On systems that support IEEE NaN, if x is a quiet NaN, that
             value is returned.  If x is a signaling NaN, a quiet NaN is
             returned and the invalid operation exception is raised.  In
             either case, errno is set to EDOM.

             In the -Xt compilation mode, the error handling procedures may
             be changed with the function matherr.

       REFERENCES
             exp(3M), matherr(3M)




















                           Copyright 1994 Novell, Inc.               Page 1