30 Input/output library [input.output]

30.7 Formatting and manipulators [iostream.format]

30.7.5 Output streams [output.streams]

30.7.5.2 Formatted output functions [ostream.formatted]

30.7.5.2.3 basic_­ostream​::​operator<< [ostream.inserters]

basic_ostream<charT, traits>& operator<<(basic_ostream<charT, traits>& (*pf)(basic_ostream<charT, traits>&));

Effects: None. Does not behave as a formatted output function (as described in [ostream.formatted.reqmts]).

Returns: pf(*this).321

basic_ostream<charT, traits>& operator<<(basic_ios<charT, traits>& (*pf)(basic_ios<charT, traits>&));

Effects: Calls pf(*this). This inserter does not behave as a formatted output function (as described in [ostream.formatted.reqmts]).

Returns: *this.322

basic_ostream<charT, traits>& operator<<(ios_base& (*pf)(ios_base&));

Effects: Calls pf(*this). This inserter does not behave as a formatted output function (as described in [ostream.formatted.reqmts]).

Returns: *this.

basic_ostream<charT, traits>& operator<<(basic_streambuf<charT, traits>* sb);

Effects: Behaves as an unformatted output function. After the sentry object is constructed, if sb is null calls setstate(badbit) (which may throw ios_­base​::​failure).

Gets characters from sb and inserts them in *this. Characters are read from sb and inserted until any of the following occurs:

  • end-of-file occurs on the input sequence;

  • inserting in the output sequence fails (in which case the character to be inserted is not extracted);

  • an exception occurs while getting a character from sb.

If the function inserts no characters, it calls setstate(failbit) (which may throw ios_­base​::​​failure ([iostate.flags])). If an exception was thrown while extracting a character, the function sets failbit in error state, and if failbit is on in exceptions() the caught exception is rethrown.

Returns: *this.

basic_ostream<charT, traits>& operator<<(nullptr_t);

Effects: Equivalent to:

return *this << s;

where s is an implementation-defined NTCTS.

See, for example, the function signature endl(basic_­ostream&).

See, for example, the function signature dec(ios_­base&).