Movatterモバイル変換

erf(3) — Linux manual page

NAME \|LIBRARY \|SYNOPSIS \|DESCRIPTION \|RETURN VALUE \|ERRORS \|ATTRIBUTES \|STANDARDS \|HISTORY \|SEE ALSO \|COLOPHON

erf(3)                   Library Functions Manualerf(3)

NAME top

       erf, erff, erfl - error function

LIBRARY top

       Math library (libm,-lm)

SYNOPSIS top

#include <math.h>double erf(doublex);float erff(floatx);long double erfl(long doublex);   Feature Test Macro Requirements for glibc (seefeature_test_macros(7)):erf():           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE               || /* Since glibc 2.19: */ _DEFAULT_SOURCE               || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCEerff(),erfl():           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L               || /* Since glibc 2.19: */ _DEFAULT_SOURCE               || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

DESCRIPTION top

       These functions return the error function ofx, defined as           erf(x) = 2/sqrt(pi) * integral from 0 to x of exp(-t*t) dt

RETURN VALUE top

       On success, these functions return the value of the error function       ofx, a value in the range [-1, 1].       Ifx is a NaN, a NaN is returned.       Ifx is +0 (-0), +0 (-0) is returned.       Ifx is positive infinity (negative infinity), +1 (-1) is       returned.       Ifx is subnormal, a range error occurs, and the return value is       2*x/sqrt(pi).

ERRORS top

       Seemath_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.       These functions do not seterrno.

ATTRIBUTES top

       For an explanation of the terms used in this section, seeattributes(7).       ┌──────────────────────────────────────┬───────────────┬─────────┐       │Interface│Attribute│Value│       ├──────────────────────────────────────┼───────────────┼─────────┤       │erf(),erff(),erfl()                │ Thread safety │ MT-Safe │       └──────────────────────────────────────┴───────────────┴─────────┘

STANDARDS top

       C11, POSIX.1-2008.

HISTORY top

       C99, POSIX.1-2001.       The variant returningdouble also conforms to SVr4, 4.3BSD.

COLOPHON top

       This page is part of theman-pages (Linux kernel and C library       user-space interface documentation) project.  Information about       the project can be found at        ⟨https://www.kernel.org/doc/man-pages/⟩.  If you have a bug report       for this manual page, see       ⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.       This page was obtained from the tarball man-pages-6.15.tar.gz       fetched from       ⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on       2025-08-11.  If you discover any rendering problems in this HTML       version of the page, or you believe there is a better or more up-       to-date source for the page, or you have corrections or       improvements to the information in this COLOPHON (which isnot       part of the original manual page), send a mail to       man-pages@man7.orgLinux man-pages 6.15            2025-05-17erf(3)

Pages that refer to this page:erfc(3)

HTML rendering created 2025-09-06 byMichael Kerrisk, author ofThe Linux Programming Interface.

For details of in-depthLinux/UNIX system programming training courses that I teach, lookhere.

Hosting byjambit GmbH.