NAME

erf, erfc − Error functions

LIBRARY

Math Library (libm.a)

SYNOPSIS

#include <math.h>

double erf   (double x);
float  erff  (float  x);
double erfc  (double x);
float  erfcf (float  x);

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

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