Hi Claus,
do print ("READ START",x) ; res <- readFile x ; print ("READ STOP",x) ; return res
Unless you've defined your own version of 'readFile', to mean read entire file now, the first 'print' is optimistic and the second 'print' is a lie.
readFile calls openFile >>= hGetContents. It's the openFile that causes the problem, so READ START happens before openFile and READ STOP happens after openFile. The lazy semantics of the actual reading don't seem to have an effect. I did try changing to the strict bytestring file read, and that gave exactly the same error - apart from openBinaryFile was crashing rather than openFile. Thanks Neil
do print ("WRITE START",x); writeFile x src ; print ("WRITE STOP",x)
I then get on the console:
WRITE START foo WRITE STOP foo READ START foo openFile doesn't have permission to open foo.
The writeFile/readFile are happening in different threads, and they usually succeed - but not always. The bug seems to go away when I add performGC just after writeFile. My guess is that something in the openFile/hClose pair isn't really closed until a garbage collection happens. All this is using GHC 6.10.2 on XP through Cygwin.
I'm happy to supply more details if you can think of anything that will help,
Thanks
Neil _______________________________________________ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users