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: The deleted overloads of
operator<<
prevent formatting characters as integers and strings as pointers
. —
end note ]
explicit basic_ostream(basic_streambuf<charT, traits>* sb);
Effects:
Initializes the base class subobject with
basic_ios<charT, traits>::init(sb) (
[basic.ios.cons])
. Postconditions:
rdbuf() == sb. basic_ostream(basic_ostream&& rhs);
Effects:
Move constructs from the rvalue
rhs. This is accomplished by default constructing the base class and calling
basic_ios<charT, traits>::move(rhs) to initialize the
base class
.virtual ~basic_ostream();
Remarks:
Does not perform any operations on
rdbuf(). basic_ostream& operator=(basic_ostream&& rhs);
Effects:
Equivalent to:
swap(rhs). void swap(basic_ostream& rhs);
Effects:
Calls
basic_ios<charT, traits>::swap(rhs).
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;
Each seek member function begins execution by constructing an object of class
sentry. It returns by destroying the
sentry object
. Returns:
If
fail() != false,
returns
pos_type(-1)
to indicate failure
. Otherwise, returns
rdbuf()->pubseekoff(0, cur, out).basic_ostream<charT, traits>& seekp(pos_type pos);
Effects:
If
fail() != true,
executes
rdbuf()->pubseekpos(pos, ios_base::out). In case of failure, the function calls
setstate(failbit)
(which may throw
ios_base::failure)
.basic_ostream<charT, traits>& seekp(off_type off, ios_base::seekdir dir);
Effects:
If
fail() != true,
executes
rdbuf()->pubseekoff(off, dir, ios_base::out). In case of failure, the function calls
setstate(failbit)
(which may throw
ios_base::failure)
.