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The C and C++ Include Header Files

cat -n /usr/include/c++/15/ext/string_conversions.h

     1	// String Conversions -*- C++ -*-
     2	
     3	// Copyright (C) 2008-2025 Free Software Foundation, Inc.
     4	//
     5	// This file is part of the GNU ISO C++ Library.  This library is free
     6	// software; you can redistribute it and/or modify it under the
     7	// terms of the GNU General Public License as published by the
     8	// Free Software Foundation; either version 3, or (at your option)
     9	// any later version.
    10	
    11	// This library is distributed in the hope that it will be useful,
    12	// but WITHOUT ANY WARRANTY; without even the implied warranty of
    13	// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    14	// GNU General Public License for more details.
    15	
    16	// Under Section 7 of GPL version 3, you are granted additional
    17	// permissions described in the GCC Runtime Library Exception, version
    18	// 3.1, as published by the Free Software Foundation.
    19	
    20	// You should have received a copy of the GNU General Public License and
    21	// a copy of the GCC Runtime Library Exception along with this program;
    22	// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
    23	// <http://www.gnu.org/licenses/>.
    24	
    25	/** @file ext/string_conversions.h
    26	 *  This file is a GNU extension to the Standard C++ Library.
    27	 */
    28	
    29	#ifndef _STRING_CONVERSIONS_H
    30	#define _STRING_CONVERSIONS_H 1
    31	
    32	#ifdef _GLIBCXX_SYSHDR
    33	#pragma GCC system_header
    34	#endif
    35	
    36	#include <bits/requires_hosted.h> // GNU extensions are currently omitted
    37	
    38	#if __cplusplus < 201103L
    39	# include <bits/c++0x_warning.h>
    40	#else
    41	
    42	#include <bits/c++config.h>
    43	#include <ext/numeric_traits.h>
    44	#include <bits/functexcept.h>
    45	#include <cstdlib>
    46	#include <cwchar>
    47	#include <cstdio>
    48	#include <cerrno>
    49	
    50	namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
    51	{
    52	_GLIBCXX_BEGIN_NAMESPACE_VERSION
    53	
    54	  // Helper for all the sto* functions.
    55	  template<typename _TRet, typename _Ret = _TRet, typename _CharT,
    56		   typename... _Base>
    57	    _Ret
    58	    __stoa(_TRet (*__convf) (const _CharT*, _CharT**, _Base...),
    59		   const char* __name, const _CharT* __str, std::size_t* __idx,
    60		   _Base... __base)
    61	    {
    62	      _Ret __ret;
    63	
    64	      _CharT* __endptr;
    65	
    66	      struct _Save_errno {
    67		_Save_errno() : _M_errno(errno) { errno = 0; }
    68		~_Save_errno() { if (errno == 0) errno = _M_errno; }
    69		int _M_errno;
    70	      } const __save_errno;
    71	
    72	      struct _Range_chk {
    73		  static bool
    74		  _S_chk(_TRet, std::false_type) { return false; }
    75	
    76		  static bool
    77		  _S_chk(_TRet __val, std::true_type) // only called when _Ret is int
    78		  {
    79		    return __val < _TRet(__numeric_traits<int>::__min)
    80		      || __val > _TRet(__numeric_traits<int>::__max);
    81		  }
    82	      };
    83	
    84	      const _TRet __tmp = __convf(__str, &__endptr, __base...);
    85	
    86	      if (__endptr == __str)
    87		std::__throw_invalid_argument(__name);
    88	      else if (errno == ERANGE
    89		  || _Range_chk::_S_chk(__tmp, std::is_same<_Ret, int>{}))
    90		std::__throw_out_of_range(__name);
    91	      else
    92		__ret = __tmp;
    93	
    94	      if (__idx)
    95		*__idx = __endptr - __str;
    96	
    97	      return __ret;
    98	    }
    99	
   100	  // Helper for the to_string / to_wstring functions.
   101	  template<typename _String, typename _CharT = typename _String::value_type>
   102	    _String
   103	    __to_xstring(int (*__convf) (_CharT*, std::size_t, const _CharT*,
   104					 __builtin_va_list), std::size_t __n,
   105			 const _CharT* __fmt, ...)
   106	    {
   107	      // XXX Eventually the result should be constructed in-place in
   108	      // the __cxx11 string, likely with the help of internal hooks.
   109	      _CharT* __s = static_cast<_CharT*>(__builtin_alloca(sizeof(_CharT)
   110								  * __n));
   111	
   112	      __builtin_va_list __args;
   113	      __builtin_va_start(__args, __fmt);
   114	
   115	      const int __len = __convf(__s, __n, __fmt, __args);
   116	
   117	      __builtin_va_end(__args);
   118	
   119	      return _String(__s, __s + __len);
   120	    }
   121	
   122	_GLIBCXX_END_NAMESPACE_VERSION
   123	} // namespace
   124	
   125	#endif // C++11
   126	
   127	#endif // _STRING_CONVERSIONS_H