w_pow_template.c 1.7 KB

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  1. /* Wrapper to set errno for pow.
  2. Copyright (C) 2017-2019 Free Software Foundation, Inc.
  3. This file is part of the GNU C Library.
  4. The GNU C Library is free software; you can redistribute it and/or
  5. modify it under the terms of the GNU Lesser General Public
  6. License as published by the Free Software Foundation; either
  7. version 2.1 of the License, or (at your option) any later version.
  8. The GNU C Library is distributed in the hope that it will be useful,
  9. but WITHOUT ANY WARRANTY; without even the implied warranty of
  10. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  11. Lesser General Public License for more details.
  12. You should have received a copy of the GNU Lesser General Public
  13. License along with the GNU C Library; if not, see
  14. <http://www.gnu.org/licenses/>. */
  15. /* Only build wrappers from the templates for the types that define the macro
  16. below. This macro is set in math-type-macros-<type>.h in sysdeps/generic
  17. for each floating-point type. */
  18. #if __USE_WRAPPER_TEMPLATE
  19. # include <errno.h>
  20. # include <fenv.h>
  21. # include <math.h>
  22. # include <math_private.h>
  23. FLOAT
  24. M_DECL_FUNC (__pow) (FLOAT x, FLOAT y)
  25. {
  26. FLOAT z = M_SUF (__ieee754_pow) (x, y);
  27. if (__glibc_unlikely (!isfinite (z)))
  28. {
  29. if (isfinite (x) && isfinite (y))
  30. {
  31. if (isnan (z))
  32. /* Domain error: pow(x<0,y=non-integer). */
  33. __set_errno (EDOM);
  34. else
  35. /* Pole error: pow(x=0,y<0). Or overflow. */
  36. __set_errno (ERANGE);
  37. }
  38. }
  39. else if (__glibc_unlikely (z == 0) && isfinite (x) && x != 0 && isfinite (y))
  40. /* Underflow. */
  41. __set_errno (ERANGE);
  42. return z;
  43. }
  44. declare_mgen_alias (__pow, pow)
  45. #endif /* __USE_WRAPPER_TEMPLATE. */