Given the necessity for fibers::asio::round_robin to share its ready queue
among all threads calling io_service::run() on the same io_service instance,
the capability to allow hop (or not) in the fibers::asio::yield mechanism is
redundant.
Add a note to the condition_variable::wait_for(..., pred) overload.
fiber_specific_ptr::reset() has no default argument.
Remove mention of launch policy deferred, since no API accepts a launch
policy argument.
Copy construction or copy assignment of a shared_future leaves other.valid()
unchanged. It won't be 'true' unless it was 'true' before.
Mention that [shared_]future::get_exception_ptr() does not invalidate.
Note that 'blocks' and 'suspends' are used interchangeably.
Add some cross-references; add link to std::allocator_arg_t. Clarify the
cross-reference to the paragraph describing BOOST_FIBERS_NO_ATOMICS.
Reformat some overly-long source lines.
This covers both generic callbacks (adapt_callbacks.cpp,
adapt_method_calls.cpp) and custom Asio completion tokens (yield.hpp,
promise_completion_token.hpp, detail/yield.hpp, detail/promise_handler.hpp).
Mark up the relevant source files to provide code snippets for callbacks.qbk.
