Where Online Learning is simpler!

The C and C++ Include Header Files

cat -n /usr/include/c++/15/print

     1	// <print> Print functions -*- C++ -*-
     2	
     3	// Copyright The GNU Toolchain Authors.
     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 include/print
    26	 *  This is a Standard C++ Library header.
    27	 */
    28	
    29	#ifndef _GLIBCXX_PRINT
    30	#define _GLIBCXX_PRINT 1
    31	
    32	#ifdef _GLIBCXX_SYSHDR
    33	#pragma GCC system_header
    34	#endif
    35	
    36	#include <bits/requires_hosted.h> // for std::format
    37	
    38	#define __glibcxx_want_print
    39	#include <bits/version.h>
    40	
    41	#ifdef __cpp_lib_print // C++ >= 23
    42	
    43	#include <format>
    44	#include <cstdio>
    45	#include <cerrno>
    46	#include <bits/functexcept.h>
    47	
    48	#ifdef _WIN32
    49	# include <system_error>
    50	#endif
    51	
    52	namespace std _GLIBCXX_VISIBILITY(default)
    53	{
    54	_GLIBCXX_BEGIN_NAMESPACE_VERSION
    55	
    56	  inline void
    57	  vprint_nonunicode(FILE* __stream, string_view __fmt, format_args __args)
    58	  {
    59	    __format::_Str_sink<char> __buf;
    60	    std::vformat_to(__buf.out(), __fmt, __args);
    61	    auto __out = __buf.view();
    62	    if (std::fwrite(__out.data(), 1, __out.size(), __stream) != __out.size())
    63	      __throw_system_error(EIO);
    64	  }
    65	
    66	  inline void
    67	  vprint_unicode(FILE* __stream, string_view __fmt, format_args __args)
    68	  {
    69	#if !defined(_WIN32) || defined(__CYGWIN__)
    70	    // For most targets we don't need to do anything special to write
    71	    // Unicode to a terminal.
    72	    std::vprint_nonunicode(__stream, __fmt, __args);
    73	#else
    74	    __format::_Str_sink<char> __buf;
    75	    std::vformat_to(__buf.out(), __fmt, __args);
    76	    auto __out = __buf.view();
    77	
    78	    void* __open_terminal(FILE*);
    79	    error_code __write_to_terminal(void*, span<char>);
    80	    // If stream refers to a terminal, write a native Unicode string to it.
    81	    if (auto __term = __open_terminal(__stream))
    82	      {
    83		string __out = std::vformat(__fmt, __args);
    84		error_code __e;
    85		if (!std::fflush(__stream))
    86		  {
    87		    __e = __write_to_terminal(__term, __out);
    88		    if (!__e)
    89		      return;
    90		    if (__e == std::make_error_code(errc::illegal_byte_sequence))
    91		      return;
    92		  }
    93		else
    94		  __e = error_code(errno, generic_category());
    95		_GLIBCXX_THROW_OR_ABORT(system_error(__e, "std::vprint_unicode"));
    96	      }
    97	
    98	    // Otherwise just write the string to the file as vprint_nonunicode does.
    99	    if (std::fwrite(__out.data(), 1, __out.size(), __stream) != __out.size())
   100	      __throw_system_error(EIO);
   101	#endif
   102	  }
   103	
   104	  template<typename... _Args>
   105	    inline void
   106	    print(FILE* __stream, format_string<_Args...> __fmt, _Args&&... __args)
   107	    {
   108	      auto __fmtargs = std::make_format_args(__args...);
   109	      if constexpr (__unicode::__literal_encoding_is_utf8())
   110		std::vprint_unicode(__stream, __fmt.get(), __fmtargs);
   111	      else
   112		std::vprint_nonunicode(__stream, __fmt.get(), __fmtargs);
   113	    }
   114	
   115	  template<typename... _Args>
   116	    inline void
   117	    print(format_string<_Args...> __fmt, _Args&&... __args)
   118	    { std::print(stdout, __fmt, std::forward<_Args>(__args)...); }
   119	
   120	  template<typename... _Args>
   121	    inline void
   122	    println(FILE* __stream, format_string<_Args...> __fmt, _Args&&... __args)
   123	    {
   124	      std::print(__stream, "{}\n",
   125			 std::format(__fmt, std::forward<_Args>(__args)...));
   126	    }
   127	
   128	  template<typename... _Args>
   129	    inline void
   130	    println(format_string<_Args...> __fmt, _Args&&... __args)
   131	    { std::println(stdout, __fmt, std::forward<_Args>(__args)...); }
   132	
   133	  inline void
   134	  vprint_unicode(string_view __fmt, format_args __args)
   135	  { std::vprint_unicode(stdout, __fmt, __args); }
   136	
   137	  inline void
   138	  vprint_nonunicode(string_view __fmt, format_args __args)
   139	  { std::vprint_nonunicode(stdout, __fmt, __args); }
   140	
   141	  // Defined for C++26, supported as an extension to C++23.
   142	  inline void println(FILE* __stream)
   143	  {
   144	#if defined(_WIN32) && !defined(__CYGWIN__)
   145	    if constexpr (__unicode::__literal_encoding_is_utf8())
   146	      std::vprint_unicode(__stream, "\n", std::make_format_args());
   147	    else
   148	#endif
   149	      if (std::putc('\n', __stream) == EOF)
   150		__throw_system_error(EIO);
   151	  }
   152	
   153	  inline void println() { std::println(stdout); }
   154	
   155	_GLIBCXX_END_NAMESPACE_VERSION
   156	} // namespace std
   157	#endif // __cpp_lib_print
   158	#endif // _GLIBCXX_PRINT