math/w_scalb_template.c

   1 /* Wrapper to set errno for scalb.
   2    Copyright (C) 2020-2024 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 /* Only build wrappers from the templates for the types that define the macro
  20    below.  This macro is set in math-type-macros-<type>.h in sysdeps/generic
  21    for each floating-point type.  */
  22 #if __USE_WRAPPER_TEMPLATE
  23
  24 #include <errno.h>
  25 #include <math.h>
  26 #include <math_private.h>
  27
  28 /* Wrapper scalb */
  29 FLOAT M_DECL_FUNC (__scalb) (FLOAT x, FLOAT fn)
  30 {
  31   FLOAT z = M_SUF (__ieee754_scalb) (x, fn);
  32
  33   if (__glibc_unlikely (!isfinite (z) || z == M_LIT (0.0)))
  34     {
  35       if (isnan (z))
  36         {
  37           if (!isnan (x) && !isnan (fn))
  38             __set_errno (EDOM);
  39         }
  40       else if (isinf (z))
  41         {
  42           if (!isinf (x) && !isinf (fn))
  43             __set_errno (ERANGE);
  44         }
  45       else
  46         {
  47           /* z == 0.  */
  48           if (x != M_LIT (0.0) && !isinf (fn))
  49             __set_errno (ERANGE);
  50         }
  51     }
  52   return z;
  53 }
  54
  55 /* Don't provide _FloatN aliases for scalb which is a deprecated interface,
  56    was obsolescent in POSIX.1-2001, removed in POSIX.1-2008, never made to
  57    C standard.  */
  58 #undef libm_alias_float_other_r
  59 #define libm_alias_float_other_r(from, to, r)
  60 #undef libm_alias_double_other_r
  61 #define libm_alias_double_other_r(from, to, r)
  62 #undef libm_alias_ldouble_other_r
  63 #define libm_alias_ldouble_other_r(from, to, r)
  64 #undef libm_alias_float128_other_r
  65 #define libm_alias_float128_other_r(from, to, r)
  66
  67 declare_mgen_alias (__scalb, scalb);
  68
  69 #endif /* __USE_WRAPPER_TEMPLATE.  */