Intrusive containers have similar same thread-safety guarantees than STL containers.
Some Intrusive hooks (auto-unlink hooks, for example) modify containers without having a reference to them: this is considered a write access to the container.
Other functions, like checking if an objects is already inserted in a containers
member of safe hooks is a read-access to the container without having a reference
to them, so no other thread should have write access (direct or indirect) to
Since the same object can be inserted in several containers at the same time using different hooks, the thread safety of Boost.Intrusive is related to the containers and also the object whose lifetime is manually managed by the user.
As we can see, the analysis of the thread-safety of a program using Boost.Intrusive is harder than with non-intrusive containers.
To analyze the thread-safety, take in care the following points:
unlink()functions modify the container indirectly.
is_linked()function is a read access to the container.