Mercurial > gnulib
view lib/hypot.c @ 17363:5a51fb7777a9
sys_select, sys_time: port 2013-01-30 Solaris 2.6 fix to Cygwin
Problem reported by Marco Atzeri in
<http://lists.gnu.org/archive/html/bug-gnulib/2013-03/msg00000.html>.
* lib/sys_select.in.h [HAVE_SYS_SELECT_H && _CYGWIN_SYS_TIME_H]:
Simply delegate to the system <sys/select.h> in this case too.
Also, pay attention to _GL_SYS_SELECT_H_REDIRECT_FROM_SYS_TIME_H only
if OSF/1, since otherwise Cygwin breaks, and it doesn't seem to
be needed on Solaris either.
* lib/sys_time.in.h [_CYGWIN_SYS_TIME_H]:
Simply delgate to the system <sys/time.h> in this case.
author | Paul Eggert <eggert@cs.ucla.edu> |
---|---|
date | Tue, 19 Mar 2013 09:08:47 -0700 |
parents | e542fd46ad6f |
children | 344018b6e5d7 |
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/* Hypotenuse of a right-angled triangle. Copyright (C) 2012-2013 Free Software Foundation, Inc. This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. This program 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 General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. */ /* Written by Bruno Haible <bruno@clisp.org>, 2012. */ #include <config.h> /* Specification. */ #include <math.h> double hypot (double x, double y) { if (isfinite (x) && isfinite (y)) { /* Determine absolute values. */ x = fabs (x); y = fabs (y); { /* Find the bigger and the smaller one. */ double a; double b; if (x >= y) { a = x; b = y; } else { a = y; b = x; } /* Now 0 <= b <= a. */ { int e; double an; double bn; /* Write a = an * 2^e, b = bn * 2^e with 0 <= bn <= an < 1. */ an = frexp (a, &e); bn = ldexp (b, - e); { double cn; /* Through the normalization, no unneeded overflow or underflow will occur here. */ cn = sqrt (an * an + bn * bn); return ldexp (cn, e); } } } } else { if (isinf (x) || isinf (y)) /* x or y is infinite. Return +Infinity. */ return HUGE_VAL; else /* x or y is NaN. Return NaN. */ return x + y; } }