#include <math.h>

       double erfc(double x);
       float erfcf(float x);
       long double erfcl(long double x);

       Link with -lm.

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

           _POSIX_C_SOURCE >= 200112L;
           or cc -std=c99
       erfcf(), erfcl():
           _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600||
           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L;
           or cc -std=c99

       The erfc() function returns the complementary error function of x, that
       is, 1.0 - erf(x).

       On success, these functions return the complementary error function  of
       x, a value in the range [0,2].

       If x is a NaN, a NaN is returned.

       If x is +0 or -0, 1 is returned.

       If x is positive infinity, +0 is returned.

       If x is negative infinity, +2 is returned.

       If  the  function  result  underflows  and  produces an unrepresentable
       value, the return value is 0.0.

       If the function result underflows but produces a  representable  (i.e.,
       subnormal) value, that value is returned, and a range error occurs.

       See  math_error(7) for information on how to determine whether an error
       has occurred when calling these functions.

       The following errors can occur:

       Range error: result underflow (result is subnormal)
              An underflow floating-point exception (FE_UNDERFLOW) is raised.

       These functions do not set errno.

       This  page  is  part of release 3.35 of the Linux man-pages project.  A
       description of the project, and information about reporting  bugs,  can
       be found at

GNU                               2010-09-20                           ERFC(3)
Man Pages Copyright Respective Owners. Site Copyright (C) 1994 - 2017 Hurricane Electric. All Rights Reserved.