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FABS(3)                    Linux Programmer's Manual                   FABS(3)
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():
           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
               || /* Since glibc 2.19: */ _DEFAULT_SOURCE
               || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
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).
       +-------------------------+---------------+---------+
       |Interface                | Attribute     | Value   |
       +-------------------------+---------------+---------+
       |fabs(), fabsf(), fabsl() | Thread safety | MT-Safe |
       +-------------------------+---------------+---------+
CONFORMING TO
       C99, POSIX.1-2001, POSIX.1-2008.
       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 4.15 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
       https://www.kernel.org/doc/man-pages/.
                                  2017-09-15                           FABS(3)