May 2001 - Glasgow-haskell-users

RE: catchAllIO
by Simon Marlow 02 May '01

02 May '01

> Dear all, I keep getting problems with expections. In the example > > catchAllIO ( action ) $ \ any -> return "foo" > > is it guaranteed that *no* exception that is raised in `action' > propagates to the outside? Yes. > (This is with ghc-4.08. Should I upgrade? Well, I will upgrade > sometime anyway, but would it help with respect to this problem?) In GHC 5.00, 'catchAllIO' is now called 'Exception.catch', and the IOError and Exception types are now isomorphic. Various other functions in the Exception library have had names changes too. Cheers, Simon

1 0

RE: ghci, -O
by Simon Marlow 02 May '01

02 May '01

> Now, as I see that ghci can load and run the code made by -O, > I wonder what the User's Guide means by saying > "-O does not work with GHCi". Maybe ghci -O ? > could be meaningful? "ghci -O" is exactly the combination that doesn't work. Cheers, Simon

1 0

Exceptions and sockets
by Johannes Waldmann 02 May '01

02 May '01

OK now I upgraded to ghc-5.00 but the situation didn't change. My suspicion is that it's not the fault of `catch'. I think what happens is this: I `Socket.accept' a connection and get a handle. Now, if the connections dies, but I still write to the handle, the whole thing crashes - without throwing an exception. (I checked that the RTS thinks `hIsWritable h' even if `h' does no longer exist in reality.) How could I work around this? SocketPrim? -- -- Johannes Waldmann ---- http://www.informatik.uni-leipzig.de/~joe/ -- -- joe(a)informatik.uni-leipzig.de -- phone/fax (+49) 341 9732 204/252 --

2 1

catchAllIO
by Johannes Waldmann 02 May '01

02 May '01

Dear all, I keep getting problems with expections. In the example catchAllIO ( action ) $ \ any -> return "foo" is it guaranteed that *no* exception that is raised in `action' propagates to the outside? (This is with ghc-4.08. Should I upgrade? Well, I will upgrade sometime anyway, but would it help with respect to this problem?) Regards, -- -- Johannes Waldmann ---- http://www.informatik.uni-leipzig.de/~joe/ -- -- joe(a)informatik.uni-leipzig.de -- phone/fax (+49) 341 9732 204/252 --

1 0

ghci, -O
by S.D.Mechveliani 02 May '01

02 May '01

I fear there is certain misunderstanding about -O usage with ghc-5.00 interactive. Simon Marlow and User's Guide (Section 4.4) say that > -O does not work with ghci. > For technical reason, the bytecode compiler doesn't interact > well with one of the optimization passes > [..] What is a bytecode compiler? The one that prepares a lightly compiled code for the interpreter? What I meant is something like this: to compile ghc -c -O Foo.hs in the batch mode and then run ghci ... Preude> :load Foo ... Foo> sm [1..9999000] I tried this with certain small function Foo.sm, and it works, and runs better than when compied with -Onot. Now, as I see that ghci can load and run the code made by -O, I wonder what the User's Guide means by saying "-O does not work with GHCi". Maybe ghci -O ? could be meaningful? ----------------- Serge Mechveliani mechvel(a)botik.ru

1 0