libstdc++
print
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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