Good morning again,

Thank you for answering.

I am using ghc 5.04.1 I compiled myself on a linux box (Mandrake 8.2) .

I'm sending you the source code. Compiled it with the following commands :

ghc -ffi -c GetFNamesBckp.hs -o GetFNamesBckp.o

gcc -I/opt/installed/ghc-5.04.1/lib/ghc-5.04.1/include -c cGetFNamesBckp.c -o cGetFNamesBckp.o

ghc -no-hs-main GetFNamesBckp_stub.o GetFNamesBckp.o cGetFNamesBckp.o

Good bug! In fact, it has nothing to do with the FFI, but it is a bug in the garbage collector introduced in 5.04.1. The fix will be in 5.04.2. BTW, an easier way to compile your program is ghc -ffi -no-hs-main cGetFNamesBckp.c GetFNamesBckp.hs Cheers, Simon