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 <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
23
24       erfcf(), erfcl():
25           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
26               || /* Since glibc 2.19: */ _DEFAULT_SOURCE
27               || /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
28

DESCRIPTION

30       These  functions return the complementary error function of x, that is,
31       1.0 - erf(x).
32

RETURN VALUE

34       On success, these functions return the complementary error function  of
35       x, a value in the range [0,2].
36
37       If x is a NaN, a NaN is returned.
38
39       If x is +0 or -0, 1 is returned.
40
41       If x is positive infinity, +0 is returned.
42
43       If x is negative infinity, +2 is returned.
44
45       If  the  function  result  underflows  and  produces an unrepresentable
46       value, the return value is 0.0.
47
48       If the function result underflows but produces a  representable  (i.e.,
49       subnormal) value, that value is returned, and a range error occurs.
50

ERRORS

52       See  math_error(7) for information on how to determine whether an error
53       has occurred when calling these functions.
54
55       The following errors can occur:
56
57       Range error: result underflow (result is subnormal)
58              An underflow floating-point exception (FE_UNDERFLOW) is raised.
59
60       These functions do not set errno.
61

ATTRIBUTES

63       For an  explanation  of  the  terms  used  in  this  section,  see  at‐
64       tributes(7).
65
66       ┌────────────────────────────────────────────┬───────────────┬─────────┐
67Interface                                   Attribute     Value   
68       ├────────────────────────────────────────────┼───────────────┼─────────┤
69erfc(), erfcf(), erfcl()                    │ Thread safety │ MT-Safe │
70       └────────────────────────────────────────────┴───────────────┴─────────┘
71

CONFORMING TO

73       C99, POSIX.1-2001, POSIX.1-2008.
74
75       The variant returning double also conforms to SVr4, 4.3BSD.
76

NOTES

78       The  erfc(),  erfcf(),  and erfcl() functions are provided to avoid the
79       loss accuracy that would occur for the calculation 1-erf(x)  for  large
80       values of x (for which the value of erf(x) approaches 1).
81

SEE ALSO

83       cerf(3), erf(3), exp(3)
84

COLOPHON

86       This  page  is  part of release 5.12 of the Linux man-pages project.  A
87       description of the project, information about reporting bugs,  and  the
88       latest     version     of     this    page,    can    be    found    at
89       https://www.kernel.org/doc/man-pages/.
90
91
92
93GNU                               2021-03-22                           ERFC(3)
Impressum