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

 

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.  

COLOPHON

This page is part of release 3.74 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at http://www.kernel.org/doc/man-pages/.

Willie has over 15 years of experience in Linux system administration and DevOps. After managing infrastructure for startups and enterprises alike, he founded Command Linux to share the practical knowledge he wished he had when starting out. He oversees content strategy and contributes guides on server management, automation, and security.