| Safe Haskell | Safe |
|---|---|
| Language | Haskell2010 |
Data.TLS.GHC
Description
This is the simplest implementation of thread-local storage using GHC's built-in ThreadId capabilities.
While the interface below is designed to match the other
implementations of TLS in this package, the GHC implementation can
generaly be relied upon to keep a stable copy of the TLS variable
for each ThreadId that calls getTLS. This may change in the
future, however!
Documentation
Make a new per-thread variable. This guarantees that no two
threads that execute getTLS simultaneosly will receive the same
copy of the value. Generally, to meet this guarantee there must be
AT LEAST one copy of the TLS variable for each distinct OS thread
that calls getAll. But this is a lower bound, and there may be
*more*. In particular, there could be one per Haskell IO thread
rather than per OS thread.
Thread safe.
getTLS :: TLS a -> IO a Source #
Fetch this thread's copy of the TLS variable. Note that all
values returned by this function may be immune to garbage collected
until freeTLS is called.
Thread safe.
allTLS :: TLS a -> IO [a] Source #
After a TLS-based computation is complete, iterate through all the copies of the TLS variable which were used by all threads.
NOT thread safe.
forEachTLS_ :: TLS a -> (a -> IO ()) -> IO () Source #
Like allTLS, but apply a computation directly rather than
building a list.
freeAllTLS :: TLS a -> IO () Source #
Release all copies of the TLS variable, across all threads. This does not guarantee the storage will be freed immediately, but it guarantees that the storage can be reclaimed in the future.
The TLS value is still usable after this call, but any future calls
to getTLS must initialize new state.
Not thread safe.