ERFC(3)                   OpenBSD Programmer's Manual                  ERFC(3)

NAME
     erf, erff, erfc, erfcf - error function operators

SYNOPSIS
     #include <math.h>

     double
     erf(double x);

     float
     erff(float x);

     double
     erfc(double x);

     float
     erfcf(float x);

DESCRIPTION
     These functions calculate the error function of x.

     The erf() calculates the error function of x, and the erff() function is
     a single precision version of erf().  The error function is defined as:

           erf(x) = 2/sqrt(pi)*integral from 0 to x of exp(-t*t) dt.

     The erfc() function calculates the complementary error function of x;
     that is erfc() subtracts the result of the error function erf(x) from
     1.0.  This is useful, since for large x places disappear.  The erfcf()
     function is a single precision version of erfc().

SEE ALSO
     math(3)

HISTORY
     The erf() and erfc() functions appeared in 4.3BSD.

OpenBSD 4.9                      May 31, 2007                      OpenBSD 4.9