olk/boost-fiber — pull request #7 by nat-goodspeed (2013-11-19 14:54:24+00:00)
Title: Fix doc about fiber::operator safe_bool(): NOT same as joinable().

Looking at the implementation, it seems that operator safe_bool() and its
companion, operator!(), interrogate whether the referenced fiber has or has
not terminated. joinable() does not.
Add more joinable() cross-references, and cross-reference joinable(), operator
safe_bool() and operator!().