Mercurial > gnulib
view lib/cbrtf.c @ 40231:9b3c79fdfe0b
strtod: fix clash with strtold
Problem reported for RHEL 5 by Jesse Caldwell (Bug#34817).
* lib/strtod.c (compute_minus_zero, minus_zero):
Simplify by remving the macro / external variable,
and having just a function. User changed. This avoids
the need for an external variable that might clash.
author | Paul Eggert <eggert@cs.ucla.edu> |
---|---|
date | Mon, 11 Mar 2019 16:40:29 -0700 |
parents | b06060465f09 |
children |
line wrap: on
line source
/* Compute cubic root of float value. Copyright (C) 1997, 2012-2019 Free Software Foundation, Inc. Contributed by Dirk Alboth <dirka@uni-paderborn.de> and Ulrich Drepper <drepper@cygnus.com>, 1997. 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 <https://www.gnu.org/licenses/>. */ #include <config.h> /* Specification. */ #include <math.h> /* MSVC with option -fp:strict refuses to compile constant initializers that contain floating-point operations. Pacify this compiler. */ #ifdef _MSC_VER # pragma fenv_access (off) #endif /* Code based on glibc/sysdeps/ieee754/flt-32/s_cbrtf.c. */ #define CBRT2 1.2599210498948731648 /* 2^(1/3) */ #define SQR_CBRT2 1.5874010519681994748 /* 2^(2/3) */ static const double factor[5] = { 1.0 / SQR_CBRT2, 1.0 / CBRT2, 1.0, CBRT2, SQR_CBRT2 }; float cbrtf (float x) { if (isfinite (x) && x != 0.0f) { float xm, ym, u, t2; int xe; /* Reduce X. XM now is an range 1.0 to 0.5. */ xm = frexpf (fabsf (x), &xe); u = (0.492659620528969547 + (0.697570460207922770 - 0.191502161678719066 * xm) * xm); t2 = u * u * u; ym = u * (t2 + 2.0 * xm) / (2.0 * t2 + xm) * factor[2 + xe % 3]; return ldexpf (x > 0.0 ? ym : -ym, xe / 3); } else return x + x; }