Guarantees regarding finalizers

[Mietek Bąk]

Hello,

I'm writing a binding to a C library, which requires an explicit
cleanup call before program termination.  While looking for a way to
automatize this, I noticed a discrepancy in the standard library
documentation.

The Foreign.Concurrent documentation states:
"The only guarantee is that the finalizer runs before the program terminates."
(http://www.haskell.org/ghc/docs/latest/html/libraries/base/Foreign-Concurrent.html)

On the other hand, the Foreign.ForeignPtr documentation states:
"Indeed, there is no guarantee that the finalizer is executed at all;
a program may exit with finalizers outstanding."
(http://www.haskell.org/ghc/docs/latest/html/libraries/base/Foreign-ForeignPtr.html)

Note that Foreign.Concurrent.newForeignPtr is implemented in GHC as
GHC.ForeignPtr.newConcForeignPtr.  The newConcForeignPtr comments also
state:
"There is no guarantee of promptness, and in fact there is no
guarantee that the finalizer will eventually run at all."
(http://www.haskell.org/ghc/docs/latest/html/libraries/base/src/GHC-ForeignPtr.html)

As much as I would like the Foreign.Concurrent guarantee to be true,
this seems to me like a documentation bug.

Best regards,

-- 
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