| // Output streams -*- C++ -*- |
| |
| // Copyright (C) 1997-2020 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/ostream |
| * This is a Standard C++ Library header. |
| */ |
| |
| // |
| // ISO C++ 14882: 27.6.2 Output streams |
| // |
| |
| #ifndef _GLIBCXX_OSTREAM |
| #define _GLIBCXX_OSTREAM 1 |
| |
| #pragma GCC system_header |
| |
| #include <ios> |
| #include <bits/ostream_insert.h> |
| |
| namespace std _GLIBCXX_VISIBILITY(default) |
| { |
| _GLIBCXX_BEGIN_NAMESPACE_VERSION |
| |
| /** |
| * @brief Template class basic_ostream. |
| * @ingroup io |
| * |
| * @tparam _CharT Type of character stream. |
| * @tparam _Traits Traits for character type, defaults to |
| * char_traits<_CharT>. |
| * |
| * This is the base class for all output streams. It provides text |
| * formatting of all builtin types, and communicates with any class |
| * derived from basic_streambuf to do the actual output. |
| */ |
| template<typename _CharT, typename _Traits> |
| class basic_ostream : virtual public basic_ios<_CharT, _Traits> |
| { |
| public: |
| // Types (inherited from basic_ios): |
| typedef _CharT char_type; |
| typedef typename _Traits::int_type int_type; |
| typedef typename _Traits::pos_type pos_type; |
| typedef typename _Traits::off_type off_type; |
| typedef _Traits traits_type; |
| |
| // Non-standard Types: |
| typedef basic_streambuf<_CharT, _Traits> __streambuf_type; |
| typedef basic_ios<_CharT, _Traits> __ios_type; |
| typedef basic_ostream<_CharT, _Traits> __ostream_type; |
| typedef num_put<_CharT, ostreambuf_iterator<_CharT, _Traits> > |
| __num_put_type; |
| typedef ctype<_CharT> __ctype_type; |
| |
| /** |
| * @brief Base constructor. |
| * |
| * This ctor is almost never called by the user directly, rather from |
| * derived classes' initialization lists, which pass a pointer to |
| * their own stream buffer. |
| */ |
| explicit |
| basic_ostream(__streambuf_type* __sb) |
| { this->init(__sb); } |
| |
| /** |
| * @brief Base destructor. |
| * |
| * This does very little apart from providing a virtual base dtor. |
| */ |
| virtual |
| ~basic_ostream() { } |
| |
| /// Safe prefix/suffix operations. |
| class sentry; |
| friend class sentry; |
| |
| ///@{ |
| /** |
| * @brief Interface for manipulators. |
| * |
| * Manipulators such as @c std::endl and @c std::hex use these |
| * functions in constructs like "std::cout << std::endl". For more |
| * information, see the iomanip header. |
| */ |
| __ostream_type& |
| operator<<(__ostream_type& (*__pf)(__ostream_type&)) |
| { |
| // _GLIBCXX_RESOLVE_LIB_DEFECTS |
| // DR 60. What is a formatted input function? |
| // The inserters for manipulators are *not* formatted output functions. |
| return __pf(*this); |
| } |
| |
| __ostream_type& |
| operator<<(__ios_type& (*__pf)(__ios_type&)) |
| { |
| // _GLIBCXX_RESOLVE_LIB_DEFECTS |
| // DR 60. What is a formatted input function? |
| // The inserters for manipulators are *not* formatted output functions. |
| __pf(*this); |
| return *this; |
| } |
| |
| __ostream_type& |
| operator<<(ios_base& (*__pf) (ios_base&)) |
| { |
| // _GLIBCXX_RESOLVE_LIB_DEFECTS |
| // DR 60. What is a formatted input function? |
| // The inserters for manipulators are *not* formatted output functions. |
| __pf(*this); |
| return *this; |
| } |
| ///@} |
| |
| ///@{ |
| /** |
| * @name Inserters |
| * |
| * All the @c operator<< functions (aka <em>formatted output |
| * functions</em>) have some common behavior. Each starts by |
| * constructing a temporary object of type std::basic_ostream::sentry. |
| * This can have several effects, concluding with the setting of a |
| * status flag; see the sentry documentation for more. |
| * |
| * If the sentry status is good, the function tries to generate |
| * whatever data is appropriate for the type of the argument. |
| * |
| * If an exception is thrown during insertion, ios_base::badbit |
| * will be turned on in the stream's error state without causing an |
| * ios_base::failure to be thrown. The original exception will then |
| * be rethrown. |
| */ |
| |
| ///@{ |
| /** |
| * @brief Integer arithmetic inserters |
| * @param __n A variable of builtin integral type. |
| * @return @c *this if successful |
| * |
| * These functions use the stream's current locale (specifically, the |
| * @c num_get facet) to perform numeric formatting. |
| */ |
| __ostream_type& |
| operator<<(long __n) |
| { return _M_insert(__n); } |
| |
| __ostream_type& |
| operator<<(unsigned long __n) |
| { return _M_insert(__n); } |
| |
| __ostream_type& |
| operator<<(bool __n) |
| { return _M_insert(__n); } |
| |
| __ostream_type& |
| operator<<(short __n); |
| |
| __ostream_type& |
| operator<<(unsigned short __n) |
| { |
| // _GLIBCXX_RESOLVE_LIB_DEFECTS |
| // 117. basic_ostream uses nonexistent num_put member functions. |
| return _M_insert(static_cast<unsigned long>(__n)); |
| } |
| |
| __ostream_type& |
| operator<<(int __n); |
| |
| __ostream_type& |
| operator<<(unsigned int __n) |
| { |
| // _GLIBCXX_RESOLVE_LIB_DEFECTS |
| // 117. basic_ostream uses nonexistent num_put member functions. |
| return _M_insert(static_cast<unsigned long>(__n)); |
| } |
| |
| #ifdef _GLIBCXX_USE_LONG_LONG |
| __ostream_type& |
| operator<<(long long __n) |
| { return _M_insert(__n); } |
| |
| __ostream_type& |
| operator<<(unsigned long long __n) |
| { return _M_insert(__n); } |
| #endif |
| ///@} |
| |
| ///@{ |
| /** |
| * @brief Floating point arithmetic inserters |
| * @param __f A variable of builtin floating point type. |
| * @return @c *this if successful |
| * |
| * These functions use the stream's current locale (specifically, the |
| * @c num_get facet) to perform numeric formatting. |
| */ |
| __ostream_type& |
| operator<<(double __f) |
| { return _M_insert(__f); } |
| |
| __ostream_type& |
| operator<<(float __f) |
| { |
| // _GLIBCXX_RESOLVE_LIB_DEFECTS |
| // 117. basic_ostream uses nonexistent num_put member functions. |
| return _M_insert(static_cast<double>(__f)); |
| } |
| |
| __ostream_type& |
| operator<<(long double __f) |
| { return _M_insert(__f); } |
| ///@} |
| |
| /** |
| * @brief Pointer arithmetic inserters |
| * @param __p A variable of pointer type. |
| * @return @c *this if successful |
| * |
| * These functions use the stream's current locale (specifically, the |
| * @c num_get facet) to perform numeric formatting. |
| */ |
| __ostream_type& |
| operator<<(const void* __p) |
| { return _M_insert(__p); } |
| |
| #if __cplusplus >= 201703L |
| __ostream_type& |
| operator<<(nullptr_t) |
| { return *this << "nullptr"; } |
| #endif |
| |
| /** |
| * @brief Extracting from another streambuf. |
| * @param __sb A pointer to a streambuf |
| * |
| * This function behaves like one of the basic arithmetic extractors, |
| * in that it also constructs a sentry object and has the same error |
| * handling behavior. |
| * |
| * If @p __sb is NULL, the stream will set failbit in its error state. |
| * |
| * Characters are extracted from @p __sb and inserted into @c *this |
| * until one of the following occurs: |
| * |
| * - the input stream reaches end-of-file, |
| * - insertion into the output sequence fails (in this case, the |
| * character that would have been inserted is not extracted), or |
| * - an exception occurs while getting a character from @p __sb, which |
| * sets failbit in the error state |
| * |
| * If the function inserts no characters, failbit is set. |
| */ |
| __ostream_type& |
| operator<<(__streambuf_type* __sb); |
| ///@} |
| |
| ///@{ |
| /** |
| * @name Unformatted Output Functions |
| * |
| * All the unformatted output functions have some common behavior. |
| * Each starts by constructing a temporary object of type |
| * std::basic_ostream::sentry. This has several effects, concluding |
| * with the setting of a status flag; see the sentry documentation |
| * for more. |
| * |
| * If the sentry status is good, the function tries to generate |
| * whatever data is appropriate for the type of the argument. |
| * |
| * If an exception is thrown during insertion, ios_base::badbit |
| * will be turned on in the stream's error state. If badbit is on in |
| * the stream's exceptions mask, the exception will be rethrown |
| * without completing its actions. |
| */ |
| |
| /** |
| * @brief Simple insertion. |
| * @param __c The character to insert. |
| * @return *this |
| * |
| * Tries to insert @p __c. |
| * |
| * @note This function is not overloaded on signed char and |
| * unsigned char. |
| */ |
| __ostream_type& |
| put(char_type __c); |
| |
| /** |
| * @brief Core write functionality, without sentry. |
| * @param __s The array to insert. |
| * @param __n Maximum number of characters to insert. |
| */ |
| void |
| _M_write(const char_type* __s, streamsize __n) |
| { |
| const streamsize __put = this->rdbuf()->sputn(__s, __n); |
| if (__put != __n) |
| this->setstate(ios_base::badbit); |
| } |
| |
| /** |
| * @brief Character string insertion. |
| * @param __s The array to insert. |
| * @param __n Maximum number of characters to insert. |
| * @return *this |
| * |
| * Characters are copied from @p __s and inserted into the stream until |
| * one of the following happens: |
| * |
| * - @p __n characters are inserted |
| * - inserting into the output sequence fails (in this case, badbit |
| * will be set in the stream's error state) |
| * |
| * @note This function is not overloaded on signed char and |
| * unsigned char. |
| */ |
| __ostream_type& |
| write(const char_type* __s, streamsize __n); |
| ///@} |
| |
| /** |
| * @brief Synchronizing the stream buffer. |
| * @return *this |
| * |
| * If @c rdbuf() is a null pointer, changes nothing. |
| * |
| * Otherwise, calls @c rdbuf()->pubsync(), and if that returns -1, |
| * sets badbit. |
| */ |
| __ostream_type& |
| flush(); |
| |
| /** |
| * @brief Getting the current write position. |
| * @return A file position object. |
| * |
| * If @c fail() is not false, returns @c pos_type(-1) to indicate |
| * failure. Otherwise returns @c rdbuf()->pubseekoff(0,cur,out). |
| */ |
| pos_type |
| tellp(); |
| |
| /** |
| * @brief Changing the current write position. |
| * @param __pos A file position object. |
| * @return *this |
| * |
| * If @c fail() is not true, calls @c rdbuf()->pubseekpos(pos). If |
| * that function fails, sets failbit. |
| */ |
| __ostream_type& |
| seekp(pos_type); |
| |
| /** |
| * @brief Changing the current write position. |
| * @param __off A file offset object. |
| * @param __dir The direction in which to seek. |
| * @return *this |
| * |
| * If @c fail() is not true, calls @c rdbuf()->pubseekoff(off,dir). |
| * If that function fails, sets failbit. |
| */ |
| __ostream_type& |
| seekp(off_type, ios_base::seekdir); |
| |
| protected: |
| basic_ostream() |
| { this->init(0); } |
| |
| #if __cplusplus >= 201103L |
| // Non-standard constructor that does not call init() |
| basic_ostream(basic_iostream<_CharT, _Traits>&) { } |
| |
| basic_ostream(const basic_ostream&) = delete; |
| |
| basic_ostream(basic_ostream&& __rhs) |
| : __ios_type() |
| { __ios_type::move(__rhs); } |
| |
| // 27.7.3.3 Assign/swap |
| |
| basic_ostream& operator=(const basic_ostream&) = delete; |
| |
| basic_ostream& |
| operator=(basic_ostream&& __rhs) |
| { |
| swap(__rhs); |
| return *this; |
| } |
| |
| void |
| swap(basic_ostream& __rhs) |
| { __ios_type::swap(__rhs); } |
| #endif |
| |
| template<typename _ValueT> |
| __ostream_type& |
| _M_insert(_ValueT __v); |
| }; |
| |
| /** |
| * @brief Performs setup work for output streams. |
| * |
| * Objects of this class are created before all of the standard |
| * inserters are run. It is responsible for <em>exception-safe prefix and |
| * suffix operations</em>. |
| */ |
| template <typename _CharT, typename _Traits> |
| class basic_ostream<_CharT, _Traits>::sentry |
| { |
| // Data Members. |
| bool _M_ok; |
| basic_ostream<_CharT, _Traits>& _M_os; |
| |
| public: |
| /** |
| * @brief The constructor performs preparatory work. |
| * @param __os The output stream to guard. |
| * |
| * If the stream state is good (@a __os.good() is true), then if the |
| * stream is tied to another output stream, @c is.tie()->flush() |
| * is called to synchronize the output sequences. |
| * |
| * If the stream state is still good, then the sentry state becomes |
| * true (@a okay). |
| */ |
| explicit |
| sentry(basic_ostream<_CharT, _Traits>& __os); |
| |
| #pragma GCC diagnostic push |
| #pragma GCC diagnostic ignored "-Wdeprecated-declarations" |
| /** |
| * @brief Possibly flushes the stream. |
| * |
| * If @c ios_base::unitbuf is set in @c os.flags(), and |
| * @c std::uncaught_exception() is true, the sentry destructor calls |
| * @c flush() on the output stream. |
| */ |
| ~sentry() |
| { |
| // XXX MT |
| if (bool(_M_os.flags() & ios_base::unitbuf) && !uncaught_exception()) |
| { |
| // Can't call flush directly or else will get into recursive lock. |
| if (_M_os.rdbuf() && _M_os.rdbuf()->pubsync() == -1) |
| _M_os.setstate(ios_base::badbit); |
| } |
| } |
| #pragma GCC diagnostic pop |
| |
| /** |
| * @brief Quick status checking. |
| * @return The sentry state. |
| * |
| * For ease of use, sentries may be converted to booleans. The |
| * return value is that of the sentry state (true == okay). |
| */ |
| #if __cplusplus >= 201103L |
| explicit |
| #endif |
| operator bool() const |
| { return _M_ok; } |
| }; |
| |
| ///@{ |
| /** |
| * @brief Character inserters |
| * @param __out An output stream. |
| * @param __c A character. |
| * @return out |
| * |
| * Behaves like one of the formatted arithmetic inserters described in |
| * std::basic_ostream. After constructing a sentry object with good |
| * status, this function inserts a single character and any required |
| * padding (as determined by [22.2.2.2.2]). @c __out.width(0) is then |
| * called. |
| * |
| * If @p __c is of type @c char and the character type of the stream is not |
| * @c char, the character is widened before insertion. |
| */ |
| template<typename _CharT, typename _Traits> |
| inline basic_ostream<_CharT, _Traits>& |
| operator<<(basic_ostream<_CharT, _Traits>& __out, _CharT __c) |
| { return __ostream_insert(__out, &__c, 1); } |
| |
| template<typename _CharT, typename _Traits> |
| inline basic_ostream<_CharT, _Traits>& |
| operator<<(basic_ostream<_CharT, _Traits>& __out, char __c) |
| { return (__out << __out.widen(__c)); } |
| |
| // Specialization |
| template<typename _Traits> |
| inline basic_ostream<char, _Traits>& |
| operator<<(basic_ostream<char, _Traits>& __out, char __c) |
| { return __ostream_insert(__out, &__c, 1); } |
| |
| // Signed and unsigned |
| template<typename _Traits> |
| inline basic_ostream<char, _Traits>& |
| operator<<(basic_ostream<char, _Traits>& __out, signed char __c) |
| { return (__out << static_cast<char>(__c)); } |
| |
| template<typename _Traits> |
| inline basic_ostream<char, _Traits>& |
| operator<<(basic_ostream<char, _Traits>& __out, unsigned char __c) |
| { return (__out << static_cast<char>(__c)); } |
| |
| #if __cplusplus > 201703L |
| // The following deleted overloads prevent formatting character values as |
| // numeric values. |
| |
| #ifdef _GLIBCXX_USE_WCHAR_T |
| template<typename _Traits> |
| basic_ostream<char, _Traits>& |
| operator<<(basic_ostream<char, _Traits>&, wchar_t) = delete; |
| #endif // _GLIBCXX_USE_WCHAR_T |
| |
| #ifdef _GLIBCXX_USE_CHAR8_T |
| template<typename _Traits> |
| basic_ostream<char, _Traits>& |
| operator<<(basic_ostream<char, _Traits>&, char8_t) = delete; |
| #endif |
| |
| template<typename _Traits> |
| basic_ostream<char, _Traits>& |
| operator<<(basic_ostream<char, _Traits>&, char16_t) = delete; |
| |
| template<typename _Traits> |
| basic_ostream<char, _Traits>& |
| operator<<(basic_ostream<char, _Traits>&, char32_t) = delete; |
| |
| #ifdef _GLIBCXX_USE_WCHAR_T |
| #ifdef _GLIBCXX_USE_CHAR8_T |
| template<typename _Traits> |
| basic_ostream<wchar_t, _Traits>& |
| operator<<(basic_ostream<wchar_t, _Traits>&, char8_t) = delete; |
| #endif // _GLIBCXX_USE_CHAR8_T |
| |
| template<typename _Traits> |
| basic_ostream<wchar_t, _Traits>& |
| operator<<(basic_ostream<wchar_t, _Traits>&, char16_t) = delete; |
| |
| template<typename _Traits> |
| basic_ostream<wchar_t, _Traits>& |
| operator<<(basic_ostream<wchar_t, _Traits>&, char32_t) = delete; |
| #endif // _GLIBCXX_USE_WCHAR_T |
| #endif // C++20 |
| ///@} |
| |
| ///@{ |
| /** |
| * @brief String inserters |
| * @param __out An output stream. |
| * @param __s A character string. |
| * @return out |
| * @pre @p __s must be a non-NULL pointer |
| * |
| * Behaves like one of the formatted arithmetic inserters described in |
| * std::basic_ostream. After constructing a sentry object with good |
| * status, this function inserts @c traits::length(__s) characters starting |
| * at @p __s, widened if necessary, followed by any required padding (as |
| * determined by [22.2.2.2.2]). @c __out.width(0) is then called. |
| */ |
| template<typename _CharT, typename _Traits> |
| inline basic_ostream<_CharT, _Traits>& |
| operator<<(basic_ostream<_CharT, _Traits>& __out, const _CharT* __s) |
| { |
| if (!__s) |
| __out.setstate(ios_base::badbit); |
| else |
| __ostream_insert(__out, __s, |
| static_cast<streamsize>(_Traits::length(__s))); |
| return __out; |
| } |
| |
| template<typename _CharT, typename _Traits> |
| basic_ostream<_CharT, _Traits> & |
| operator<<(basic_ostream<_CharT, _Traits>& __out, const char* __s); |
| |
| // Partial specializations |
| template<typename _Traits> |
| inline basic_ostream<char, _Traits>& |
| operator<<(basic_ostream<char, _Traits>& __out, const char* __s) |
| { |
| if (!__s) |
| __out.setstate(ios_base::badbit); |
| else |
| __ostream_insert(__out, __s, |
| static_cast<streamsize>(_Traits::length(__s))); |
| return __out; |
| } |
| |
| // Signed and unsigned |
| template<typename _Traits> |
| inline basic_ostream<char, _Traits>& |
| operator<<(basic_ostream<char, _Traits>& __out, const signed char* __s) |
| { return (__out << reinterpret_cast<const char*>(__s)); } |
| |
| template<typename _Traits> |
| inline basic_ostream<char, _Traits> & |
| operator<<(basic_ostream<char, _Traits>& __out, const unsigned char* __s) |
| { return (__out << reinterpret_cast<const char*>(__s)); } |
| |
| #if __cplusplus > 201703L |
| // The following deleted overloads prevent formatting strings as |
| // pointer values. |
| |
| #ifdef _GLIBCXX_USE_WCHAR_T |
| template<typename _Traits> |
| basic_ostream<char, _Traits>& |
| operator<<(basic_ostream<char, _Traits>&, const wchar_t*) = delete; |
| #endif // _GLIBCXX_USE_WCHAR_T |
| |
| #ifdef _GLIBCXX_USE_CHAR8_T |
| template<typename _Traits> |
| basic_ostream<char, _Traits>& |
| operator<<(basic_ostream<char, _Traits>&, const char8_t*) = delete; |
| #endif // _GLIBCXX_USE_CHAR8_T |
| |
| template<typename _Traits> |
| basic_ostream<char, _Traits>& |
| operator<<(basic_ostream<char, _Traits>&, const char16_t*) = delete; |
| |
| template<typename _Traits> |
| basic_ostream<char, _Traits>& |
| operator<<(basic_ostream<char, _Traits>&, const char32_t*) = delete; |
| |
| #ifdef _GLIBCXX_USE_WCHAR_T |
| #ifdef _GLIBCXX_USE_CHAR8_T |
| template<typename _Traits> |
| basic_ostream<wchar_t, _Traits>& |
| operator<<(basic_ostream<wchar_t, _Traits>&, const char8_t*) = delete; |
| #endif |
| |
| template<typename _Traits> |
| basic_ostream<wchar_t, _Traits>& |
| operator<<(basic_ostream<wchar_t, _Traits>&, const char16_t*) = delete; |
| |
| template<typename _Traits> |
| basic_ostream<wchar_t, _Traits>& |
| operator<<(basic_ostream<wchar_t, _Traits>&, const char32_t*) = delete; |
| #endif // _GLIBCXX_USE_WCHAR_T |
| #endif // C++20 |
| ///@} |
| |
| // Standard basic_ostream manipulators |
| |
| /** |
| * @brief Write a newline and flush the stream. |
| * |
| * This manipulator is often mistakenly used when a simple newline is |
| * desired, leading to poor buffering performance. See |
| * https://gcc.gnu.org/onlinedocs/libstdc++/manual/streambufs.html#io.streambuf.buffering |
| * for more on this subject. |
| */ |
| template<typename _CharT, typename _Traits> |
| inline basic_ostream<_CharT, _Traits>& |
| endl(basic_ostream<_CharT, _Traits>& __os) |
| { return flush(__os.put(__os.widen('\n'))); } |
| |
| /** |
| * @brief Write a null character into the output sequence. |
| * |
| * <em>Null character</em> is @c CharT() by definition. For CharT |
| * of @c char, this correctly writes the ASCII @c NUL character |
| * string terminator. |
| */ |
| template<typename _CharT, typename _Traits> |
| inline basic_ostream<_CharT, _Traits>& |
| ends(basic_ostream<_CharT, _Traits>& __os) |
| { return __os.put(_CharT()); } |
| |
| /** |
| * @brief Flushes the output stream. |
| * |
| * This manipulator simply calls the stream's @c flush() member function. |
| */ |
| template<typename _CharT, typename _Traits> |
| inline basic_ostream<_CharT, _Traits>& |
| flush(basic_ostream<_CharT, _Traits>& __os) |
| { return __os.flush(); } |
| |
| #if __cplusplus >= 201103L |
| template<typename _Ch, typename _Up> |
| basic_ostream<_Ch, _Up>& |
| __is_convertible_to_basic_ostream_test(basic_ostream<_Ch, _Up>*); |
| |
| template<typename _Tp, typename = void> |
| struct __is_convertible_to_basic_ostream_impl |
| { |
| using __ostream_type = void; |
| }; |
| |
| template<typename _Tp> |
| using __do_is_convertible_to_basic_ostream_impl = |
| decltype(__is_convertible_to_basic_ostream_test |
| (declval<typename remove_reference<_Tp>::type*>())); |
| |
| template<typename _Tp> |
| struct __is_convertible_to_basic_ostream_impl |
| <_Tp, |
| __void_t<__do_is_convertible_to_basic_ostream_impl<_Tp>>> |
| { |
| using __ostream_type = |
| __do_is_convertible_to_basic_ostream_impl<_Tp>; |
| }; |
| |
| template<typename _Tp> |
| struct __is_convertible_to_basic_ostream |
| : __is_convertible_to_basic_ostream_impl<_Tp> |
| { |
| public: |
| using type = __not_<is_void< |
| typename __is_convertible_to_basic_ostream_impl<_Tp>::__ostream_type>>; |
| constexpr static bool value = type::value; |
| }; |
| |
| template<typename _Ostream, typename _Tp, typename = void> |
| struct __is_insertable : false_type {}; |
| |
| template<typename _Ostream, typename _Tp> |
| struct __is_insertable<_Ostream, _Tp, |
| __void_t<decltype(declval<_Ostream&>() |
| << declval<const _Tp&>())>> |
| : true_type {}; |
| |
| template<typename _Ostream> |
| using __rvalue_ostream_type = |
| typename __is_convertible_to_basic_ostream< |
| _Ostream>::__ostream_type; |
| |
| /** |
| * @brief Generic inserter for rvalue stream |
| * @param __os An input stream. |
| * @param __x A reference to the object being inserted. |
| * @return os |
| * |
| * This is just a forwarding function to allow insertion to |
| * rvalue streams since they won't bind to the inserter functions |
| * that take an lvalue reference. |
| */ |
| template<typename _Ostream, typename _Tp> |
| inline |
| typename enable_if<__and_<__not_<is_lvalue_reference<_Ostream>>, |
| __is_convertible_to_basic_ostream<_Ostream>, |
| __is_insertable< |
| __rvalue_ostream_type<_Ostream>, |
| const _Tp&>>::value, |
| __rvalue_ostream_type<_Ostream>>::type |
| operator<<(_Ostream&& __os, const _Tp& __x) |
| { |
| __rvalue_ostream_type<_Ostream> __ret_os = __os; |
| __ret_os << __x; |
| return __ret_os; |
| } |
| #endif // C++11 |
| |
| _GLIBCXX_END_NAMESPACE_VERSION |
| } // namespace std |
| |
| #include <bits/ostream.tcc> |
| |
| #endif /* _GLIBCXX_OSTREAM */ |