C++ named requirements: UnformattedOutputFunction

 

C++

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Named requirements

Feature test macros (C++20)

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Concepts library (C++20)

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Ranges library (C++20)

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Technical specifications

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C++ named requirements

Basic
DefaultConstructible CopyAssignable CopyConstructible	MoveAssignable (C++11) MoveConstructible (C++11) Destructible
Type properties
ScalarType TriviallyCopyable (C++11) StandardLayoutType (C++11)	PODType TrivialType (C++11) ImplicitLifetimeType (C++20)
Library-Wide
EqualityComparable LessThanComparable Swappable (C++11) ValueSwappable (C++11) NullablePointer (C++11) Hash (C++11)	Allocator FunctionObject Callable Predicate BinaryPredicate Compare
Container
Container SequenceContainer ContiguousContainer (C++17) ReversibleContainer	AssociativeContainer AllocatorAwareContainer UnorderedAssociativeContainer (C++11)
Container Elements
DefaultInsertable (C++11) CopyInsertable (C++11) MoveInsertable (C++11)	EmplaceConstructible (C++11) Erasable (C++11)
Iterator
LegacyIterator LegacyOutputIterator LegacyInputIterator LegacyForwardIterator	LegacyBidirectionalIterator LegacyRandomAccessIterator LegacyContiguousIterator (C++17) ConstexprIterator (C++20)
Stream I/O
FormattedInputFunction UnformattedInputFunction	FormattedOutputFunction UnformattedOutputFunction
Formatting
BasicFormatter (C++20)	Formatter (C++20)
Random Numbers
SeedSequence (C++11) RandomNumberEngine (C++11)	RandomNumberDistribution (C++11) UniformRandomBitGenerator (C++11) RandomNumberEngineAdaptor (C++11)
Concurrency
BasicLockable (C++11) Lockable (C++11) TimedLockable (C++11) SharedLockable (C++14) SharedTimedLockable (C++14)	Mutex (C++11) TimedMutex (C++11) SharedMutex (C++17) SharedTimedMutex (C++14)
Other
CharTraits RegexTraits (C++11) BitmaskType NumericType LiteralType (C++11)	UnaryTypeTrait (C++11) BinaryTypeTrait (C++11) TransformationTrait (C++11) Clock (C++11) TrivialClock (C++11)

 

Requirements

A UnformattedOutputFunction is a stream output function that performs the following:

• Constructs an object of type basic_ostream::sentry with automatic storage duration, which performs the following

• if eofbit or badbit are set on the output stream, sets the failbit as well, and if exceptions on failbit are enabled in this output stream's exception mask, throws ios_base::failure.
• flushes the tie()'d output stream, if applicable.

• Checks the status of the sentry by calling sentry::operator bool(), which is equivalent to basic_ios::good.
• If the sentry returned false or sentry's constructor threw an exception, no output takes place
• If the sentry returned true, attempts to perform the desired output by inserting the characters into the output stream as if by calling rdbuf()->sputc() or rdbuf()->xsputn(). Additionally, rdbuf()->overflow() and rdbuf()->sync() may be called, but no other virtual member function of std::basic_streambuf.

• if an exception is thrown during output, sets badbit in the output stream. If exceptions on badbit are enabled in this stream's exception mask, the exception is also rethrown.
• If no exception was thrown, returns the value specified by the function.

• In any event, whether terminating by exception or returning, the sentry's destructor is called before leaving this function.

Standard library

The following standard library functions are UnformattedOutputFunctions.

• basic_ostream::operator<<(basic_streambuf*)
• basic_ostream::put
• basic_ostream::write
• basic_ostream::flush

basic_ostream::tellp (except calls pubseekoff instead of output) basic_ostream::seekp (except calls pubseekoff or pubseekpos instead of output)

(since C++11)