# FABS

NAME

SYNOPSIS

DESCRIPTION

RETURN VALUE

ERRORS

ATTRIBUTES

CONFORMING TO

SEE ALSO

COLOPHON

## NAME

fabs, fabsf,
fabsl − absolute value of floating-point number

## SYNOPSIS

**#include
<math.h>**

**double
fabs(double** *x***); **

float fabsf(float *x***); **

long double fabsl(long double *x***);**

Link with
*−lm*.

Feature Test
Macro Requirements for glibc (see
**feature_test_macros**(7)):

**fabsf**(),
**fabsl**():

_BSD_SOURCE || _SVID_SOURCE ||
_XOPEN_SOURCE >= 600 || _ISOC99_SOURCE ||
_POSIX_C_SOURCE >= 200112L;

or *cc -std=c99*

## DESCRIPTION

These functions
return the absolute value of the floating-point number
*x*.

## RETURN VALUE

These functions
return the absolute value of *x*.

If *x* is
a NaN, a NaN is returned.

If *x* is
−0, +0 is returned.

If *x* is
negative infinity or positive infinity, positive infinity is
returned.

## ERRORS

No errors
occur.

## ATTRIBUTES

For an
explanation of the terms used in this section, see
**attributes**(7).

## CONFORMING TO

C99,
POSIX.1-2001. The variant returning *double* also
conforms to SVr4, 4.3BSD, C89.

## SEE ALSO

**abs**(3),
**cabs**(3), **ceil**(3), **floor**(3),
**labs**(3), **rint**(3)

## COLOPHON

This page is
part of release 3.53 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/.