ERF
Section: Linux Programmer's Manual (3)
Updated: 20100920
Index
Return to Main Contents
NAME
erf, erff, erfl,  error function
SYNOPSIS
#include <math.h>
double erf(double x);
float erff(float x);
long double erfl(long double x);
Link with lm.
Feature Test Macro Requirements for glibc (see
feature_test_macros(7)):
erf():

_BSD_SOURCE  _SVID_SOURCE  _XOPEN_SOURCE  _ISOC99_SOURCE 
_POSIX_C_SOURCE >= 200112L;
or
cc std=c99
erff(),
erfl():

_BSD_SOURCE  _SVID_SOURCE  _XOPEN_SOURCE >= 600  _ISOC99_SOURCE 
_POSIX_C_SOURCE >= 200112L;
or
cc std=c99
DESCRIPTION
The
erf()
function returns the error function of
x,
defined
as
erf(x) = 2/sqrt(pi)* integral from 0 to x of exp(t*t) dt
RETURN VALUE
On success, these functions return the error function of
x,
a value in the range [1, 1].
If
x
is a NaN, a NaN is returned.
If
x
is +0 (0), +0 (0) is returned.
If
x
is positive infinity (negative infinity),
+1 (1) is returned.
If
x
is subnormal,
a range error occurs,
and the return value is 2*x/sqrt(pi).
ERRORS
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 (x is subnormal)

An underflow floatingpoint exception
(FE_UNDERFLOW)
is raised.
These functions do not set
errno.
CONFORMING TO
C99, POSIX.12001.
The variant returning
double
also conforms to
SVr4, 4.3BSD.
SEE ALSO
cerf(3),
erfc(3),
exp(3)
COLOPHON
This page is part of release 3.54 of the Linux
manpages
project.
A description of the project,
and information about reporting bugs,
can be found at
http://www.kernel.org/doc/manpages/.
Index
 NAME

 SYNOPSIS

 DESCRIPTION

 RETURN VALUE

 ERRORS

 CONFORMING TO

 SEE ALSO

 COLOPHON

This document was created by
man2html,
using the manual pages.
Time: 01:32:18 GMT, January 23, 2018