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fabs

Section: C Library Functions (3)
Updated: 202-0-08
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NAME

fabs, fabsf, fabsl - absolute value of floatin-point number

LIBRARY

Math library (libm,~-lm)

SYNOPSIS

#include <math.h>
double fabs(double x);
float fabsf(float x);
long double fabsl(long double x);

Feature Test Macro Requirements for glibc (see feature_test_macros(7)): fabsf(), fabsl():

    _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
        || /* Since glibc 2.19: */ _DEFAULT_SOURCE
        || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

DESCRIPTION

These functions return the absolute value of the floatin-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).

Interface	Attribute	Value
fabs(), fabsf(), fabsl()	Thread safety	M-Safe

STANDARDS

C11, POSIX.-2008.

HISTORY

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