Manpages - std_basic_ostream_sentry.3

sentry (*basic_ostream*< _CharT, _Traits > &__os)
The constructor performs preparatory work.

~sentry ()
Possibly flushes the stream.

operator bool () const
Quick status checking.

class std::basic_ostream< _CharT, _Traits >::sentry“Performs setup work for output streams.

Objects of this class are created before all of the standard inserters are run. It is responsible for exception-safe prefix and suffix operations.

Definition at line 432 of file ostream.

_CharT, _Traits >::sentry::sentry (*basic_ostream*< _CharT, _Traits > & __os)= [explicit]= The constructor performs preparatory work.

Parameters

__os The output stream to guard.

If the stream state is good (__os.good() is true), then if the stream is tied to another output stream, is.tie()->flush() is called to synchronize the output sequences.

If the stream state is still good, then the sentry state becomes true (okay).

Definition at line 46 of file ostream.tcc.

References std::ios_base::failbit, std::basic_ios< _CharT, _Traits >::good(), std::basic_ios< _CharT, _Traits >::setstate(), and std::basic_ios< _CharT, _Traits >::tie().

_CharT, _Traits >::sentry::~sentry ()= [inline]= Possibly flushes the stream. If ios_base::unitbuf is set in os.flags(), and std::uncaught_exception() is true, the sentry destructor calls flush() on the output stream.

Definition at line 462 of file ostream.

_CharT, _Traits >::sentry::operator bool () const= [inline]=, = [explicit]= Quick status checking.

Returns

The sentry state.

For ease of use, sentries may be converted to booleans. The return value is that of the sentry state (true == okay).

Definition at line 484 of file ostream.