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ERF(3) | Linux Programmer's Manual | ERF(3) |
NAME¶
erf, erff, erfl, - error functionSYNOPSIS¶
#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(7)):
_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE
|| _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L;
or cc -std=c99
_BSD_SOURCE || _SVID_SOURCE ||
_XOPEN_SOURCE >= 600 || _ISOC99_SOURCE ||
_POSIX_C_SOURCE >= 200112L;
or cc -std=c99
DESCRIPTION¶
The erf() function returns the error function of x, defined as-
erf(x) = 2/sqrt(pi)* integral from 0 to x of exp(-t*t) dt
RETURN VALUE¶
On success, these functions return the error function of x, a value in the range [-1, 1].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 (x is subnormal)
- An underflow floating-point exception (FE_UNDERFLOW) is raised.
CONFORMING TO¶
C99, POSIX.1-2001. The variant returning double also conforms to SVr4, 4.3BSD.SEE ALSO¶
cerf(3), erfc(3), exp(3)COLOPHON¶
This page is part of release 3.44 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/.2010-09-20 | GNU |