glibc/math/s_fdim.c

48 lines
1.4 KiB
C

/* Return positive difference between arguments.
Copyright (C) 1997, 2004, 2009 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <errno.h>
#include <math.h>
double
__fdim (double x, double y)
{
int clsx = fpclassify (x);
int clsy = fpclassify (y);
if (clsx == FP_NAN || clsy == FP_NAN
|| (y < 0 && clsx == FP_INFINITE && clsy == FP_INFINITE))
/* Raise invalid flag. */
return x - y;
if (x <= y)
return 0.0;
double r = x - y;
if (fpclassify (r) == FP_INFINITE)
__set_errno (ERANGE);
return r;
}
weak_alias (__fdim, fdim)
#ifdef NO_LONG_DOUBLE
strong_alias (__fdim, __fdiml)
weak_alias (__fdim, fdiml)
#endif