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; or cc -std=c99

DESCRIPTION
       The fabs() 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.

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 3.23 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/.