erfc3
Complementary error function
Usage
#include <math.h>
double erfc(double x); float erfcf(float x); long double erfcl(long double x);
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 <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
erfcf(), erfcl():
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
Library
Math library (libm, -lm)
Overview
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 floating-point 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 | MT-Safe |
Notes
The erfc(), erfcf(), and erfcl() functions are provided to avoid the loss accuracy that would occur for the calculation 1-erf(x) for large values of x (for which the value of erf(x) approaches 1).
Releases
19 releases since Debian 1.1 (Buzz); the text changed 13 times.