1ERFC(3)                    Linux Programmer's Manual                   ERFC(3)
2
3
4

NAME

6       erfc, erfcf, erfcl - complementary error function
7

SYNOPSIS

9       #include <math.h>
10
11       double erfc(double x);
12       float erfcf(float x);
13       long double erfcl(long double x);
14
15       Link with -lm.
16
17   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
18
19       erfc():
20           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE
21               || /* Since glibc 2.19: */ _DEFAULT_SOURCE
22               || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
23       erfcf(), erfcl():
24           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
25               || /* Since glibc 2.19: */ _DEFAULT_SOURCE
26               || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
27

DESCRIPTION

29       These  functions return the complementary error function of x, that is,
30       1.0 - erf(x).
31

RETURN VALUE

33       On success, these functions return the complementary error function  of
34       x, a value in the range [0,2].
35
36       If x is a NaN, a NaN is returned.
37
38       If x is +0 or -0, 1 is returned.
39
40       If x is positive infinity, +0 is returned.
41
42       If x is negative infinity, +2 is returned.
43
44       If  the  function  result  underflows  and  produces an unrepresentable
45       value, the return value is 0.0.
46
47       If the function result underflows but produces a  representable  (i.e.,
48       subnormal) value, that value is returned, and a range error occurs.
49

ERRORS

51       See  math_error(7) for information on how to determine whether an error
52       has occurred when calling these functions.
53
54       The following errors can occur:
55
56       Range error: result underflow (result is subnormal)
57              An underflow floating-point exception (FE_UNDERFLOW) is raised.
58
59       These functions do not set errno.
60

ATTRIBUTES

62       For  an  explanation  of  the  terms  used   in   this   section,   see
63       attributes(7).
64
65       ┌─────────────────────────┬───────────────┬─────────┐
66       │Interface                │ Attribute     │ Value   │
67       ├─────────────────────────┼───────────────┼─────────┤
68       │erfc(), erfcf(), erfcl() │ Thread safety │ MT-Safe │
69       └─────────────────────────┴───────────────┴─────────┘

CONFORMING TO

71       C99, POSIX.1-2001, POSIX.1-2008.
72
73       The variant returning double also conforms to SVr4, 4.3BSD.
74

NOTES

76       The  erfc(),  erfcf(),  and erfcl() functions are provided to avoid the
77       loss accuracy that would occur for the calculation 1-erf(x)  for  large
78       values of x (for which the value of erf(x) approaches 1).
79

SEE ALSO

81       cerf(3), erf(3), exp(3)
82

COLOPHON

84       This  page  is  part of release 5.02 of the Linux man-pages project.  A
85       description of the project, information about reporting bugs,  and  the
86       latest     version     of     this    page,    can    be    found    at
87       https://www.kernel.org/doc/man-pages/.
88
89
90
91GNU                               2017-09-15                           ERFC(3)
Impressum