NAME

erf, erfc − Error functions

SYNOPSIS

#include <math.h>
double erf(
        double x ); float erff(
        float x ); long double erfl(
        long double x ); double erfc(
        double x ); float erfcf(
        float x ); long double erfcl(
        long double x );

LIBRARY

Math Library (libm)

STANDARDS

Interfaces documented on this reference page conform to industry standards as follows:

erf():  XPG4

erfc():  XPG4

Refer to the standards(5) reference page for more information about industry standards and associated tags. 

DESCRIPTION

The erf(), erff(), and erfl() functions return the error function of x, where erf(x), erff(x), and erfl(x) equal (2/sqrt(pi)) times the area under the curve e∗∗(−t∗∗2) between 0 and x. 

The erfc(), erfcf(),  and erfcl() functions return (1.0 − erf(x)). The erfc() function can result in an underflow as x gets large.