# erfc(3m) [ultrix man page]

```erf(3m) 																   erf(3m)

Name
erf, erfc - error functions

Syntax
#include <math.h>

double erf(x)
double x;

double erfc(x)
double x;

Description
The function returns the error function of x defined as follows:
erf(x) = 2/sqrt(pi)*integral from 0 to x of exp(-t*t) dt.

The function returns 1.0-erf(x).

The entry for the function is provided because of the extreme loss of relative accuracy if erf(x) is called for large x and the result sub-
tracted from 1.	For example if x = 10, 12 places are lost.

Return Values
The and functions return NaN when x is NaN.

math(3m)

RISC								   erf(3m)```

## Check Out this Related Man Page

```erf(3M) 						  Mathematical Library Functions						   erf(3M)

NAME
erf, erff, erfl - error function

SYNOPSIS
cc [ flag... ] file... -lm [ library... ]
#include <math.h>

double erf(double x);

float erff(float x);

long double erfl(long double x);

DESCRIPTION
These functions compute the error function of their argument x, defined as:

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

Equation that computes error function of x.

RETURN VALUES
Upon successful completion, these functions return the value of the error function.

If x is NaN, a NaN is returned.

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

If x is +-Inf, +-1 is returned.

If x is subnormal, 2/sqrt() * 2 is returned.

ATTRIBUTES
See attributes(5) for descriptions of the following attributes:

+-----------------------------+-----------------------------+
|      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
+-----------------------------+-----------------------------+
|Interface Stability	     |Standard			   |
+-----------------------------+-----------------------------+
|MT-Level		     |MT-Safe			   |
+-----------------------------+-----------------------------+