Edit File: ostream
// Output streams -*- C++ -*- // Copyright (C) 1997-2013 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); } /** * @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); } 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); /** * @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); } } /** * @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 <class _Traits> inline basic_ostream<char, _Traits>& operator<<(basic_ostream<char, _Traits>& __out, char __c) { return __ostream_insert(__out, &__c, 1); } // Signed and unsigned template<class _Traits> inline basic_ostream<char, _Traits>& operator<<(basic_ostream<char, _Traits>& __out, signed char __c) { return (__out << static_cast<char>(__c)); } template<class _Traits> inline basic_ostream<char, _Traits>& operator<<(basic_ostream<char, _Traits>& __out, unsigned char __c) { return (__out << static_cast<char>(__c)); } //@} //@{ /** * @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<class _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<class _Traits> inline basic_ostream<char, _Traits>& operator<<(basic_ostream<char, _Traits>& __out, const signed char* __s) { return (__out << reinterpret_cast<const char*>(__s)); } template<class _Traits> inline basic_ostream<char, _Traits> & operator<<(basic_ostream<char, _Traits>& __out, const unsigned char* __s) { return (__out << reinterpret_cast<const char*>(__s)); } //@} // 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 * http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt11ch25s02.html * 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 /** * @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 _CharT, typename _Traits, typename _Tp> inline basic_ostream<_CharT, _Traits>& operator<<(basic_ostream<_CharT, _Traits>&& __os, const _Tp& __x) { __os << __x; return __os; } #endif // C++11 _GLIBCXX_END_NAMESPACE_VERSION } // namespace std #include <bits/ostream.tcc> #endif /* _GLIBCXX_OSTREAM */