Hello, I need memory refreshing about FFI because I need to fix a bug (plus I got down a rat hole because of Ukraine war :-(). Following a snippet of something I wrote: -- | lock all of the memory space of a process lockAllMemory :: LockAllFlags -> IO () lockAllMemory flags = do throwErrnoIfMinus1 "lockAllMemory" (c_mlockall cflags) return () where cflags = case flags of CURRENT -> (#const MCL_CURRENT) FUTURE -> (#const MCL_FUTURE) CURRENTandFUTURE -> (#const MCL_CURRENTandFUTURE) it is a file called LockedMem.hsc and the third arm CURRENTandFUTURE I just added to fix the this bug .. MCL_CURRENTandFUTURE ends up in LockedMem_make.c(sp??) but I get a undeclared nasty message when I try to build LockedMem.hsc... my bad... . Please help so I can go back to help Ukraine. Kind regarsd, Vasya