namespace std {
template<class charT, class traits = char_traits<charT>>
class basic_ostream : virtual public basic_ios<charT, traits> {
public:
using char_type = charT;
using int_type = typename traits::int_type;
using pos_type = typename traits::pos_type;
using off_type = typename traits::off_type;
using traits_type = traits;
explicit basic_ostream(basic_streambuf<char_type, traits>* sb);
virtual ~basic_ostream();
class sentry;
basic_ostream<charT, traits>&
operator<<(basic_ostream<charT, traits>& (*pf)(basic_ostream<charT, traits>&));
basic_ostream<charT, traits>&
operator<<(basic_ios<charT, traits>& (*pf)(basic_ios<charT, traits>&));
basic_ostream<charT, traits>&
operator<<(ios_base& (*pf)(ios_base&));
basic_ostream<charT, traits>& operator<<(bool n);
basic_ostream<charT, traits>& operator<<(short n);
basic_ostream<charT, traits>& operator<<(unsigned short n);
basic_ostream<charT, traits>& operator<<(int n);
basic_ostream<charT, traits>& operator<<(unsigned int n);
basic_ostream<charT, traits>& operator<<(long n);
basic_ostream<charT, traits>& operator<<(unsigned long n);
basic_ostream<charT, traits>& operator<<(long long n);
basic_ostream<charT, traits>& operator<<(unsigned long long n);
basic_ostream<charT, traits>& operator<<(float f);
basic_ostream<charT, traits>& operator<<(double f);
basic_ostream<charT, traits>& operator<<(long double f);
basic_ostream<charT, traits>& operator<<(const void* p);
basic_ostream<charT, traits>& operator<<(nullptr_t);
basic_ostream<charT, traits>& operator<<(basic_streambuf<char_type, traits>* sb);
basic_ostream<charT, traits>& put(char_type c);
basic_ostream<charT, traits>& write(const char_type* s, streamsize n);
basic_ostream<charT, traits>& flush();
pos_type tellp();
basic_ostream<charT, traits>& seekp(pos_type);
basic_ostream<charT, traits>& seekp(off_type, ios_base::seekdir);
protected:
basic_ostream(const basic_ostream&) = delete;
basic_ostream(basic_ostream&& rhs);
basic_ostream& operator=(const basic_ostream&) = delete;
basic_ostream& operator=(basic_ostream&& rhs);
void swap(basic_ostream& rhs);
};
template<class charT, class traits>
basic_ostream<charT, traits>& operator<<(basic_ostream<charT, traits>&, charT);
template<class charT, class traits>
basic_ostream<charT, traits>& operator<<(basic_ostream<charT, traits>&, char);
template<class traits>
basic_ostream<char, traits>& operator<<(basic_ostream<char, traits>&, char);
template<class traits>
basic_ostream<char, traits>& operator<<(basic_ostream<char, traits>&, signed char);
template<class traits>
basic_ostream<char, traits>& operator<<(basic_ostream<char, traits>&, unsigned char);
template<class traits>
basic_ostream<char, traits>& operator<<(basic_ostream<char, traits>&, wchar_t) = delete;
template<class traits>
basic_ostream<char, traits>& operator<<(basic_ostream<char, traits>&, char8_t) = delete;
template<class traits>
basic_ostream<char, traits>& operator<<(basic_ostream<char, traits>&, char16_t) = delete;
template<class traits>
basic_ostream<char, traits>& operator<<(basic_ostream<char, traits>&, char32_t) = delete;
template<class traits>
basic_ostream<wchar_t, traits>&
operator<<(basic_ostream<wchar_t, traits>&, char8_t) = delete;
template<class traits>
basic_ostream<wchar_t, traits>&
operator<<(basic_ostream<wchar_t, traits>&, char16_t) = delete;
template<class traits>
basic_ostream<wchar_t, traits>&
operator<<(basic_ostream<wchar_t, traits>&, char32_t) = delete;
template<class charT, class traits>
basic_ostream<charT, traits>& operator<<(basic_ostream<charT, traits>&, const charT*);
template<class charT, class traits>
basic_ostream<charT, traits>& operator<<(basic_ostream<charT, traits>&, const char*);
template<class traits>
basic_ostream<char, traits>& operator<<(basic_ostream<char, traits>&, const char*);
template<class traits>
basic_ostream<char, traits>& operator<<(basic_ostream<char, traits>&, const signed char*);
template<class traits>
basic_ostream<char, traits>& operator<<(basic_ostream<char, traits>&, const unsigned char*);
template<class traits>
basic_ostream<char, traits>&
operator<<(basic_ostream<char, traits>&, const wchar_t*) = delete;
template<class traits>
basic_ostream<char, traits>&
operator<<(basic_ostream<char, traits>&, const char8_t*) = delete;
template<class traits>
basic_ostream<char, traits>&
operator<<(basic_ostream<char, traits>&, const char16_t*) = delete;
template<class traits>
basic_ostream<char, traits>&
operator<<(basic_ostream<char, traits>&, const char32_t*) = delete;
template<class traits>
basic_ostream<wchar_t, traits>&
operator<<(basic_ostream<wchar_t, traits>&, const char8_t*) = delete;
template<class traits>
basic_ostream<wchar_t, traits>&
operator<<(basic_ostream<wchar_t, traits>&, const char16_t*) = delete;
template<class traits>
basic_ostream<wchar_t, traits>&
operator<<(basic_ostream<wchar_t, traits>&, const char32_t*) = delete;
}
The class template
basic_ostream
defines a number of member function
signatures that assist in formatting and writing output to output sequences
controlled by a stream buffer
. They may use other public members of
basic_ostream
except that they shall not invoke any virtual members of
rdbuf()
except
overflow(),
xsputn(),
and
sync(). If one of these called functions throws an exception, then unless explicitly noted otherwise
the output function sets
badbit
in the error state
. If
badbit
is set in
exceptions(),
the output function
rethrows the exception without completing its actions, otherwise
it does not throw anything and proceeds as if the called function had returned
a failure indication
.[
Note 1:
The deleted overloads of
operator<<
prevent formatting characters as integers and strings as pointers
. —
end note]
namespace std {
template<class charT, class traits = char_traits<charT>>
class basic_ostream<charT, traits>::sentry {
bool ok_;
public:
explicit sentry(basic_ostream<charT, traits>& os);
~sentry();
explicit operator bool() const { return ok_; }
sentry(const sentry&) = delete;
sentry& operator=(const sentry&) = delete;
};
}
The class
sentry
defines a class that is responsible for doing exception safe prefix and suffix
operations
.explicit sentry(basic_ostream<charT, traits>& os);
If
os.good()
is nonzero, prepares for formatted or unformatted output
. If
os.tie()
is not a null pointer, calls
os.tie()->flush().If, after any preparation is completed,
os.good()
is
true,
ok_ == true
otherwise,
ok_ == false. During preparation, the constructor may call
setstate(failbit)
(which may throw
ios_base::failure (
[iostate.flags]))
.If
(os.flags() & ios_base::unitbuf) && !uncaught_exceptions()
&& os.good()
is
true,
calls
os.rdbuf()->pubsync(). If that function returns -1, sets
badbit in
os.rdstate() without propagating an exception
.explicit operator bool() const;