std_abs.h

Go to the documentation of this file.

// -*- C++ -*- C library enhancements header.
 
// Copyright (C) 2016-2026 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library 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, or (at your option)
// any later version.
 
// This 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 General Public License for more details.
 
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
 
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
// <http://www.gnu.org/licenses/>.
 
/** @file include/bits/std_abs.h
 *  This is an internal header file, included by other library headers.
 *  Do not attempt to use it directly. @headername{cmath, cstdlib}
 */
 
#ifndef _GLIBCXX_BITS_STD_ABS_H
#define _GLIBCXX_BITS_STD_ABS_H
 
#ifdef _GLIBCXX_SYSHDR
#pragma GCC system_header
#endif
 
#include <bits/c++config.h>
 
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wpedantic" // include_next
#pragma GCC diagnostic ignored "-Wlong-long"
 
#define _GLIBCXX_INCLUDE_NEXT_C_HEADERS
#include_next <stdlib.h>
#ifdef __CORRECT_ISO_CPP_MATH_H_PROTO
# include_next <math.h>
#endif
#undef _GLIBCXX_INCLUDE_NEXT_C_HEADERS
 
#undef abs
 
extern "C++"
{
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
 
  using ::abs;
 
#ifndef __CORRECT_ISO_CPP_STDLIB_H_PROTO
  inline long
  abs(long __i) { return __builtin_labs(__i); }
#endif
 
#ifdef _GLIBCXX_USE_LONG_LONG
  inline long long
  abs(long long __x) { return __builtin_llabs (__x); }
#endif
 
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// 2192. Validity and return type of std::abs(0u) is unclear
// 2294. <cstdlib> should declare abs(double)
// 2735. std::abs(short), std::abs(signed char) and others should return int
 
#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR double
  abs(double __x)
  { return __builtin_fabs(__x); }
 
  inline _GLIBCXX_CONSTEXPR float
  abs(float __x)
  { return __builtin_fabsf(__x); }
 
  inline _GLIBCXX_CONSTEXPR long double
  abs(long double __x)
  { return __builtin_fabsl(__x); }
#endif
 
#if defined(__GLIBCXX_TYPE_INT_N_0)
  __extension__ inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_0
  abs(__GLIBCXX_TYPE_INT_N_0 __x) { return __x >= 0 ? __x : -__x; }
#endif
#if defined(__GLIBCXX_TYPE_INT_N_1)
  __extension__ inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_1
  abs(__GLIBCXX_TYPE_INT_N_1 __x) { return __x >= 0 ? __x : -__x; }
#endif
#if defined(__GLIBCXX_TYPE_INT_N_2)
  __extension__ inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_2
  abs(__GLIBCXX_TYPE_INT_N_2 __x) { return __x >= 0 ? __x : -__x; }
#endif
#if defined(__GLIBCXX_TYPE_INT_N_3)
  __extension__ inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_3
  abs(__GLIBCXX_TYPE_INT_N_3 __x) { return __x >= 0 ? __x : -__x; }
#endif
 
#if defined __STRICT_ANSI__ && defined __SIZEOF_INT128__
  // In strict modes __GLIBCXX_TYPE_INT_N_0 is not defined for __int128,
  // but we want to always define std::abs(__int128).
  __extension__ inline _GLIBCXX_CONSTEXPR __int128
  abs(__int128 __x) { return __x >= 0 ? __x : -__x; }
#endif
 
#if defined(__STDCPP_FLOAT16_T__) && defined(_GLIBCXX_FLOAT_IS_IEEE_BINARY32)
  constexpr _Float16
  abs(_Float16 __x)
  { return _Float16(__builtin_fabsf(__x)); }
#endif
 
#if defined(__STDCPP_FLOAT32_T__) && defined(_GLIBCXX_FLOAT_IS_IEEE_BINARY32)
  constexpr _Float32
  abs(_Float32 __x)
  { return __builtin_fabsf(__x); }
#endif
 
#if defined(__STDCPP_FLOAT64_T__) && defined(_GLIBCXX_DOUBLE_IS_IEEE_BINARY64)
  constexpr _Float64
  abs(_Float64 __x)
  { return __builtin_fabs(__x); }
#endif
 
#if defined(__STDCPP_FLOAT128_T__) && defined(_GLIBCXX_LDOUBLE_IS_IEEE_BINARY128)
  constexpr _Float128
  abs(_Float128 __x)
  { return __builtin_fabsl(__x); }
#elif defined(__STDCPP_FLOAT128_T__) && defined(_GLIBCXX_HAVE_FLOAT128_MATH)
  constexpr _Float128
  abs(_Float128 __x)
  { return __builtin_fabsf128(__x); }
#endif
 
#if defined(__STDCPP_BFLOAT16_T__) && defined(_GLIBCXX_FLOAT_IS_IEEE_BINARY32)
  constexpr __gnu_cxx::__bfloat16_t
  abs(__gnu_cxx::__bfloat16_t __x)
  { return __gnu_cxx::__bfloat16_t(__builtin_fabsf(__x)); }
#endif
 
#if defined(_GLIBCXX_USE_FLOAT128) && !defined(__CUDACC__)
  __extension__ inline _GLIBCXX_CONSTEXPR
  __float128
  abs(__float128 __x)
  {
#if defined(_GLIBCXX_LDOUBLE_IS_IEEE_BINARY128)
    return __builtin_fabsl(__x);
#elif defined(_GLIBCXX_HAVE_FLOAT128_MATH)
    return __builtin_fabsf128(__x);
#else
    // Assume that __builtin_signbit works for __float128.
    return __builtin_signbit(__x) ? -__x : __x;
#endif
  }
#endif
 
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace
} // extern "C++"
 
#pragma GCC diagnostic pop
 
#endif // _GLIBCXX_BITS_STD_ABS_H