fabs: 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

Multithreading (see pthreads(7))

The fabs(), fabsf(), and fabsl() functions are thread-safe.

CONFORMING TO

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

RELATED TO fabs…

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

COLOPHON

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fabs (3)