ERFC
Section: Linux Programmer's Manual (3)
Updated: 20170915
Index
Return to Main Contents
NAME
erfc, erfcf, erfcl  complementary error function
SYNOPSIS
#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)):
erfc():

_ISOC99_SOURCE  _POSIX_C_SOURCE >= 200112L  _XOPEN_SOURCE
 /* Since glibc 2.19: */ _DEFAULT_SOURCE
 /* Glibc versions <= 2.19: */ _BSD_SOURCE  _SVID_SOURCE
erfcf(),
erfcl():

_ISOC99_SOURCE  _POSIX_C_SOURCE >= 200112L
 /* Since glibc 2.19: */ _DEFAULT_SOURCE
 /* Glibc versions <= 2.19: */ _BSD_SOURCE  _SVID_SOURCE
DESCRIPTION
These functions return the complementary error function of
x,
that is, 1.0  erf(x).
RETURN VALUE
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.
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 (result is subnormal)

An underflow floatingpoint exception
(FE_UNDERFLOW)
is raised.
These functions do not set
errno.
ATTRIBUTES
For an explanation of the terms used in this section, see
attributes(7).
Interface  Attribute  Value

erfc(),
erfcf(),
erfcl()
 Thread safety  MTSafe

CONFORMING TO
C99, POSIX.12001, POSIX.12008.
The variant returning
double
also conforms to
SVr4, 4.3BSD.
NOTES
The
erfc(),
erfcf(),
and
erfcl()
functions are provided to avoid the loss accuracy that
would occur for the calculation 1erf(x) for large values of
x
(for which the value of erf(x) approaches 1).
SEE ALSO
cerf(3),
erf(3),
exp(3)
COLOPHON
This page is part of release 4.15 of the Linux
manpages
project.
A description of the project,
information about reporting bugs,
and the latest version of this page,
can be found at
https://www.kernel.org/doc/manpages/.
Index
 NAME

 SYNOPSIS

 DESCRIPTION

 RETURN VALUE

 ERRORS

 ATTRIBUTES

 CONFORMING TO

 NOTES

 SEE ALSO

 COLOPHON

This document was created by
man2html,
using the manual pages.
Time: 09:06:31 GMT, September 26, 2018