- Glasgow-haskell-users

RE: Evacuated Object
by Simon Peyton-Jones 28 May '01

28 May '01

The error means that GHC's garbage collector has come across something it doesn't understand. It's either a bug in the GHC garbage collector, or in GHCi itself (which plays fast and loose with types in one or two places) or in something to do with the SDL graphics interface. Bugs like this are really hard to find, unless we can reproduce them here. Can you send us all the code? Simon | -----Original Message----- | From: John Knottenbelt [mailto:jak97@doc.ic.ac.uk] | Sent: 27 May 2001 19:24 | To: glasgow-haskell-users(a)haskell.org | Subject: Evacuated Object | | | I'm experimenting with GHC (5.00.1) on RedHat Linux 7.1, it's foreign | function interface (using .hsc files) and the SDL graphics | library (v1.2). | The curious thing is that the following code: | | main = sdlInit [sdlVideo[ | sdlQuit | | can be loaded into GHCi and executed as many times as I like, | however, if I then carry on and edit the module containing | main, and then perform a | reload (:r), I sometimes get an "EVACUATED object entered!" | message and GHC | crashes on me: | | TestGraphics> :r | Compiling TestGraphics ( TestGraphics.hs, interpreted ) | Ok, modules loaded: TestGraphics, SDL, Rectangle, SDLEvents, | SDLKeySyms, | ForeignUtil. | TestGraphics> main | EVACUATED object entered! | make: *** [interactive] Error 1 | bash$ | | What does this error mean, and why is it only triggered when | I perform a | reload in GHCi? | | Sometimes the reload works fine, and other times I get a | segmentation fault. | | Thanks | | John | | _______________________________________________ | Glasgow-haskell-users mailing list | Glasgow-haskell-users(a)haskell.org | http://www.haskell.org/mailman/listinfo/glasgow-| haskell-users |

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Evacuated Object
by John Knottenbelt 27 May '01

27 May '01

I'm experimenting with GHC (5.00.1) on RedHat Linux 7.1, it's foreign function interface (using .hsc files) and the SDL graphics library (v1.2). The curious thing is that the following code: main = sdlInit [sdlVideo[ sdlQuit can be loaded into GHCi and executed as many times as I like, however, if I then carry on and edit the module containing main, and then perform a reload (:r), I sometimes get an "EVACUATED object entered!" message and GHC crashes on me: TestGraphics> :r Compiling TestGraphics ( TestGraphics.hs, interpreted ) Ok, modules loaded: TestGraphics, SDL, Rectangle, SDLEvents, SDLKeySyms, ForeignUtil. TestGraphics> main EVACUATED object entered! make: *** [interactive] Error 1 bash$ What does this error mean, and why is it only triggered when I perform a reload in GHCi? Sometimes the reload works fine, and other times I get a segmentation fault. Thanks John

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ghc-5.00.1 is available
by Julian Seward (Intl Vendor) 26 May '01

26 May '01

The (Interactive) Glasgow Haskell Compiler -- version 5.00.1 ============================================================== We are pleased to announce a new patchlevel release of the Glasgow Haskell Compiler (GHC), version 5.00.1. The source distribution is freely available via the World-Wide Web and through anon. FTP, under a BSD-style license. See below for download details. Pre-built packages for Linux, FreeBSD, and Solaris(sparc) are also available. Haskell is a standard lazy functional programming language; the current language version is Haskell 98, agreed in December 1998. GHC is a state-of-the-art programming suite for Haskell. Included is an optimising compiler generating good code for a variety of platforms, together with an interactive system for convenient, quick development. The distribution includes space and time profiling facilities, a large collection of libraries, and support for various language extensions, including concurrency, exceptions, and foreign language interfaces (C, C++, whatever). A wide variety of Haskell related resources (tutorials, libraries, specifications, documentation, compilers, interpreters, references, contact information, links to research groups) are available from the Haskell home page at http://www.haskell.org/ GHC's Web page lives at http://www.haskell.org/ghc/ What's new in 5.00.1 ====================== This is a bug-fix release. Most reported bugs in 5.00 have been fixed, including a substantial number of show-stopping bugs. The system should be much more usable for more people. Upgrading to 5.00.1 is recommended. To all those who tried out 5.00 and reported bugs, we thank you for your feedback and patience. At the moment there is no Win32 build of 5.00 or 5.00.1 available. We decided to push Win32 support to the 5.02 release, so as not to delay 5.00.1 any further. What's new in 5.00 ==================== 5.00 has been majorly revamped since the previous stable version, 4.08.2. This should be a stable release. Major changes since 4.08.2 are: - An interactive system, similar in style to Hugs. You can interactively load and unload modules, run expressions, ask the types of things. Module dependencies are tracked and chased automatically. Combinations of compiled and interpreted modules may be used. All the GHC libraries are available in interactive mode, as are most of the Glasgow extensions to Haskell 98. Compilation in interactive mode (to bytecode) is about three times faster than compiling to object code. - Batch compilation of multiple modules at once, with automatic dependency chasing. For large programs this can halve compilation times, and removes the need for Makefiles. - Enhanced package (library) management system. Packages may be installed and removed from an installation using the ghc-pkg tool. - Initial Unicode support - the Char type is now 31 bits. - Sparc native code generator, giving much faster compilation on sparcs. (Native code generation for x86s has been available for a while). - Improved heap profiling - you can restrict heap profiles by type, closure description, cost centre, and module. - Support for the latest Foreign Function Interface (FFI) proposals. Marcin Kowalczyk's hsc2hs tool is included. - Language extensions: parallel list comprehensions and functional dependencies. - The usual huge collection of bug fixes. Most reported bugs have been fixed. For full details see the release notes: http://www.haskell.org/ghc/docs/5.00/set/release-5-00.html How to get it =============== The easy way is to go to the WWW page, which should be self-explanatory: http://www.haskell.org/ghc/ We supply binary builds in .rpm/.deb form for all you Linux junkies out there, and in InstallShield form for Windows folks. Everybody else gets a .tar.gz which can be installed where you want. Once you have the distribution, please follow the pointers in the README file to find all of the documentation about this release. On-line GHC-related resources =============================== Relevant URLs on the World-Wide Web: GHC home page http://www.haskell.org/ghc/ Haskell home page http://www.haskell.org/ comp.lang.functional FAQ http://www.cs.nott.ac.uk/~gmh/faq.html System requirements ===================== To compile programs with GHC, you need a machine with 32+MB memory, GNU C and perl. This release is known to work on the following platforms: * i386-unknown-{linux,freebsd,mingw32} * sparc-sun-solaris2 Ports to the following platforms should be relatively easy (for a wunderhacker), but haven't been tested due to lack of time/hardware: * hppa1.1-hp-hpux{9,10} * i386-unknown-solaris2 * alpha-dec-osf{2,3} * mips-sgi-irix{5,6} * {rs6000,powerpc}-ibm-aix The builder's guide included in distribution gives a complete run-down of what ports work; an on-line version can be found at http://www.haskell.org/ghc/docs/5.00/building/building-guide.html Mailing lists =============== We run mailing lists for GHC users and bug reports; to subscribe, use the web interfaces at http://www.haskell.org/mailman/listinfo/glasgow-haskell-users http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs There are several other haskell and ghc-related mailing lists on www.haskell.org; for the full list, see http://www.haskell.org/mailman/listinfo/ Please send bug reports about GHC to glasgow-haskell-bugs(a)haskell.org; GHC users hang out on glasgow-haskell-users(a)haskell.org. Bleeding edge CVS users party on cvs-ghc(a)haskell.org.

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GHCi 5.00.1: packages can now be loaded at the prompt
by Simon Marlow 25 May '01

25 May '01

A new feature slipped into 5.00.1, but it looks like the documentation to go with it didn't get merged (probably my fault, sorry about that). You can now load packages from the GHCi prompt, like so: ___ ___ _ / _ \ /\ /\/ __(_) / /_\// /_/ / / | | GHC Interactive, version 5.00.1, For Haskell 98. / /_\\/ __ / /___| | http://www.haskell.org/ghc/ \____/\/ /_/\____/|_| Type :? for help. Loading package std ... linking ... :done. Prelude> :set -package lang Loading package lang ... linking ... done. Prelude> :set -package util Loading package concurrent ... linking ... done. Loading package posix ... linking ... done. Loading package util ... linking ... done. Prelude> This means you can also load packages from .ghci files too. Cheers, Simon

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RE: building from source in User's guide
by Simon Marlow 25 May '01

25 May '01

> GHC-5.xxx User's Guide explains binary installation. > But I cannot find there about making from sources. > Am I missing something? The Building Guide is a separate document, available on-line here: http://www.haskell.org/ghc/docs/latest/building/building-guide.html Cheers, Simon

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building from source in User's guide
by S.D.Mechveliani 25 May '01

25 May '01

GHC-5.xxx User's Guide explains binary installation. But I cannot find there about making from sources. Am I missing something? ----------------- Serge Mechveliani mechvel(a)botik.ru

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RE: Poll: System.exitWith behaviour
by Simon Marlow 25 May '01

25 May '01

> I think, having the third point is good, because the Haskell > report requires that > > Computation exitWith code terminates the program, > returning code to the program's caller. Either way we still conform to the report in the case of a single threaded program (actually, we've already deviated from the report in allowing you to catch the ExitException and carry on). For a multi-threaded program, it's not clear to me what exitWith should do. What should happen if a Haskell callback invokes exitWith? Should it terminate the Haskell main thread? I must admit I'm leaning more towards omitting the third point, and that's what I've implemented for now. Cheers, Simon

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Re: ghc-5.00.1 is available
by Steinitz, Dominic J 24 May '01

24 May '01

Of course I meant hPutStr handle (map (chr .word8ToInt) protocolElement) Dominic J Steinitz@baexternal 24/05/2001 18:47 To: v-julsew cc: glasgow-haskell-users haskell bcc: Dominic Steinitz Subject: Re: ghc-5.00.1 is available Will this - Initial Unicode support - the Char type is now 31 bit cause me a problem? I am sending protocol elements via a socket. I represent these as [Word8]. I had assumed that when I want to send something I do hPutStr (map (ord .word8ToInt) protocolElement) essentially doing a type coercion. But this looks like bits actually get changed into something the respondent won't recognise. Dominic. -------------------------------------------------------------------------------- ----------------- 21st century air travel http://www.britishairways.com _______________________________________________ Haskell mailing list Haskell(a)haskell.org http://www.haskell.org/mailman/listinfo/haskell ------------------------------------------------------------------------------------------------- 21st century air travel http://www.britishairways.com

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Re: ghc-5.00.1 is available
by Steinitz, Dominic J 24 May '01

24 May '01

Will this - Initial Unicode support - the Char type is now 31 bit cause me a problem? I am sending protocol elements via a socket. I represent these as [Word8]. I had assumed that when I want to send something I do hPutStr (map (ord .word8ToInt) protocolElement) essentially doing a type coercion. But this looks like bits actually get changed into something the respondent won't recognise. Dominic. ------------------------------------------------------------------------------------------------- 21st century air travel http://www.britishairways.com

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RE: Endangered I/O operations
by Simon Marlow 24 May '01

24 May '01

> A related wish I have is that a Haskell program receiving a HUP signal > should flush its buffers before terminating. > > Or even better, flush on some other signal that does not terminate > the program. Well, you can catch HUP in the program and initiate a flush. Actually just doing System.exitWith will cause all the open handles to be flushed and closed, but note that if you do System.exitWith from a signal handler it won't terminate the program any more... ;-) I think we've just found an argument in favour of having System.exitWith always terminate the program even from a child thread. If you want to *just* flush all the open handles from a signal handler, you'll need to keep track of the open handles and flush them by hand from the signal handler. See the Posix library documentation for details on setting up a signal handler. Cheers, Simon

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