29 Input/output library [input.output]

29.11 Synchronized output streams [syncstream]

29.11.3 Class template basic_­osyncstream [syncstream.osyncstream] Construction and destruction [syncstream.osyncstream.cons]

basic_osyncstream(streambuf_type* buf, const Allocator& allocator);
Effects: Initializes sb from buf and allocator.
Initializes the base class with basic_­ostream<charT, traits>(addressof(sb)).
[Note 1:
The member functions of the provided stream buffer can be called from emit() while a lock is held, which might result in a deadlock if used incautiously.
— end note]
Postconditions: get_­wrapped() == buf is true.
basic_osyncstream(basic_osyncstream&& other) noexcept;
Effects: Move constructs the base class and sb from the corresponding subobjects of other, and calls basic_­ostream<charT, traits>​::​set_­rdbuf(addressof(sb)).
Postconditions: The value returned by get_­wrapped() is the value returned by os.get_­wrapped() prior to calling this constructor.
nullptr == other.get_­wrapped() is true.