Package: ghc6
Version: 6.10.4-1
Severity: normal
Hello,
The following program will run normally, but when it exits an
error is reported:
/---------------------------------
import System.Posix.Semaphore
main = do
s <- semOpen "c" (OpenSemFlags True False) 0666 1
semThreadWait s
v <- semGetValue s
putStrLn "Type!"
a <- getLine
putStrLn $ "OK, " ++ a
semPost s
\---------------------------------
When I run it:
/---------------------------------
$ ghc sem.hs -lpthread -o sem
$ ./sem
Type!
abc
OK, abc
sem: error: a C finalizer called back into Haskell.
This was previously allowed, but is disallowed in GHC 6.10.2 and later.
To create finalizers that may call back into Haskll, use
Foreign.Concurrent.newForeignPtr instead of Foreign.newForeignPtr.
\---------------------------------
It makes no difference if there is another instance of the program
already using the semaphore (the error is produced regardless of
wether the process slept or not).
It also makes no difference wether the semaphore existed before the
program started.
The error seems to happen because a C function called via FFI tried
to call back into Haskell code (at least it's what I understood).
J.
-- System Information:
Debian Release: squeeze/sid
APT prefers unstable
APT policy: (500, 'unstable'), (1, 'experimental')
Architecture: amd64 (x86_64)
Kernel: Linux 2.6.31-rc7 (SMP w/2 CPU cores; PREEMPT)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8) (ignored: LC_ALL
set to en_US.UTF-8)
Shell: /bin/sh linked to /bin/bash
Versions of packages ghc6 depends on:
ii gcc 4:4.3.3-9 The GNU C compiler
ii libc6 2.9-25 GNU C Library: Shared libraries
ii libffi-dev 3.0.7-1 Foreign Function Interface library
ii libffi5 3.0.7-1 Foreign Function Interface library
ii libgmp3-dev 2:4.3.1+dfsg-3 Multiprecision arithmetic library
ii libgmp3c2 2:4.3.1+dfsg-3 Multiprecision arithmetic library
ii perl [perl5] 5.10.0-25 Larry Wall's Practical Extraction
ghc6 recommends no packages.
Versions of packages ghc6 suggests:
ii ghc6-doc 6.10.4-1 Documentation for the Glasgow Hask
ii ghc6-prof 6.10.4-1 Profiling libraries for the Glasgo
pn haskell-doc <none> (no description available)
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