Интерактивная система просмотра системных руководств (man-ов) erff (3) erff ( FreeBSD man: Библиотечные вызовы ) erff ( Русские man: Библиотечные вызовы ) >> erff ( Linux man: Библиотечные вызовы ) erff ( POSIX man: Библиотечные вызовы )
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
erf ():
_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE || _ISOC99_SOURCE; or
cc -std=c99
erff (),
erfl ():
_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600|| _ISOC99_SOURCE; or
cc -std=c99
DESCRIPTION
The
erf ()
function returns the error function of x , defined
as
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
The following errors can occur:
Range error: result underflow (x is subnormal)
An underflow floating-point exception
(FE_UNDERFLOW )
is raised.
These functions do not set
errno .
CONFORMING TO
C99, POSIX.1-2001.
The variant returning
double
also conforms to
SVr4, 4.3BSD.
SEE ALSO
cerf erfc exp
COLOPHON
This page is part of release 3.14 of the Linux
man-pages
project.
A description of the project,
and information about reporting bugs,
can be found at
http://www.kernel.org/doc/man-pages/.
Index
NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
ERRORS
CONFORMING TO
SEE ALSO
COLOPHON
