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C stack frames need to be returned in exactly the same order they were created Re: FFI and threads: abrupt exit 71
by Mikael 24 Fév '13

24 Fév '13

Dimitris, (From only looking very generally at your code,) May this be a stack unwinding problem? If you unwind a stack other than in the same order it was wound in the first place, your Gambit process will terminate or at least crash. Example: You have a lambda A that invokes C-lambda B that invokes lambda C. Also, a lambda D that invokes C-lambda E that invokes lambda F. If you invoke A and A invokes B and B invokes C, and then say, Gambit switches thread, and that Gambit thread invokes D which invokes E which invokes F, and then, say, Gambit switches thread again, and that Gambit thread returns from C to B. Then your Gambit process is toast. To handle this you can switch off Gambit's threading system when you're in B or E for the course of your C and F calls respectively. Note that switching off Gambit's threading system means that some or several of Gambit's built-in IO primitives would block forever. See the "How to work with external libraries" Wiki page for how to switch it off. Was this of help? Mikael 2013/2/23 Dimitris Vyzovitis <vyzo(a)hackzen.org> > I am running into an abrupt exit with error code 71 (OSError) when > multiple (scheme) threads are making ffi calls that upcall to scheme. > > A simplified scenario (see attached file) is as follows: > 2 or more threads make an ffi call. > The ffi call is a longer running procedure, that makes upcalls into > scheme procedures that do I/O. > This results in the program exiting abruptly with error code 71, and > no context information regarding the error (even when compiled and > running with full debugging). > > For an illustration of the problem, see the attached file. > > The following should print dots indefinitely, but instead quickly > terminates with 71. > > $ gsc exit71.scm > $ gsi -e "(begin (load \"exit71\") (main))" > ....<plenty of dots>.... $ echo $? > 71 > > This is with gambit-4.6.6, system is GNU/Linux x86-64. > > -- vyzo > > _______________________________________________ > Gambit-list mailing list > Gambit-list(a)iro.umontreal.ca > https://webmail.iro.umontreal.ca/mailman/listinfo/gambit-list > >

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Build script for Visual Studio 2012/11.0
by Karl Heinrichmeyer 23 Fév '13

23 Fév '13

Hi, I was experimenting with building gambit with Visual Studio 2012 Express and managed to create libgambc.lib, gsi.exe and gsc.exe by patching misc/vc2008. The patched version is attached. The gsi.exe starts and seems to work but I did no further tests (sadly I don't have the time right now). Nevertheless this might be useful for somebody else. Gambit looks great and thanks to everyone who works on it. Best regards, Karl

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FFI and threads: abrupt exit 71
by Dimitris Vyzovitis 23 Fév '13

23 Fév '13

I am running into an abrupt exit with error code 71 (OSError) when multiple (scheme) threads are making ffi calls that upcall to scheme. A simplified scenario (see attached file) is as follows: 2 or more threads make an ffi call. The ffi call is a longer running procedure, that makes upcalls into scheme procedures that do I/O. This results in the program exiting abruptly with error code 71, and no context information regarding the error (even when compiled and running with full debugging). For an illustration of the problem, see the attached file. The following should print dots indefinitely, but instead quickly terminates with 71. $ gsc exit71.scm $ gsi -e "(begin (load \"exit71\") (main))" ....<plenty of dots>.... $ echo $? 71 This is with gambit-4.6.6, system is GNU/Linux x86-64. -- vyzo

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Combining Emacs and Gambit
by Steve Graham 21 Fév '13

21 Fév '13

I've reviewed the web page on this and have: 1) Created a .emacs file in the /home/steve/emacs.d directory and put the following lines in it: (autoload 'gambit-inferior-mode "gambit" "Hook Gambit mode into cmuscheme.") (autoload 'gambit-mode "gambit" "Hook Gambit mode into scheme.") (add-hook 'inferior-scheme-mode-hook (function gambit-inferior-mode)) (add-hook 'scheme-mode-hook (function gambit-mode)) (setq scheme-program-name "gsi -:d-") 2) I've copied gambit.el into the same directory from /usr/lib/gambit/misc/gambit.el When I start emacs, and key M-x run-scheme, emacs responds with: Searching for program: no such file or directory, scheme Any help on how to integrate emacs with Gambit? Thanks, Steve

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Wiki back online
by Marc Feeley 21 Fév '13

21 Fév '13

The Gambit wiki is now back online. The faulty hard disk has now been replaced with a SSD drive, so I expect a more reliable system now. If you find issues with the wiki (pages or data missing, features that don't work as expected) please let me know. Marc

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Error building 4.6.7
by Steve Graham 20 Fév '13

20 Fév '13

Just downloaded 4.6.7 to my Linux Mint 14 (x64) system. In following the quick installation instructions in README, I got an error in the make step: ../gsc-boot -:~~bin=../bin,~~lib=../lib,~~include=../include -f -c -check _t-c-3.scm *** ERROR -- Can't find file "/usr/lib/gambc-v4_6_7-devel/gsc/_t-c-3.scm" make[1]: *** [_t-c-3.c] Error 70 make[1]: Leaving directory `/usr/lib/gambc-v4_6_7-devel/gsc' make: *** [all-recursive] Error 1 steve@steve-Satellite-L555D /usr/lib/gambc-v4_6_7-devel $ The odd thing is that the file does exist: steve@steve-Satellite-L555D /usr/lib/gambc-v4_6_7-devel $ cd gsc steve@steve-Satellite-L555D /usr/lib/gambc-v4_6_7-devel/gsc $ ls -al _t-c-3.scm -rw------- 1 501 501 13399 Jun 14 2012 _t-c-3.scm steve@steve-Satellite-L555D /usr/lib/gambc-v4_6_7-devel/gsc $ pwd /usr/lib/gambc-v4_6_7-devel/gsc Steve

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Problems with site
by Steve Graham 20 Fév '13

20 Fév '13

Still having problems loading http://gambitscheme.org/wiki/

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[ANN] Gambit-C v4.6.7 released
by gambit＠iro.umontreal.ca 19 Fév '13

19 Fév '13

Gambit-C v4.6.7 is now available. Changelog: https://github.com/feeley/gambit/commits The sources and prebuilt distributions can be obtained from the Gambit web site by visiting one of the following links. sources: http://www.iro.umontreal.ca/~gambit/download/gambit/v4.6/source/gambc-v4_6_… (for typical users) http://www.iro.umontreal.ca/~gambit/download/gambit/v4.6/source/gambc-v4_6_… (for developers) prebuilt: http://www.iro.umontreal.ca/~gambit/download/gambit/v4.6/prebuilt/gambc-v4_… http://www.iro.umontreal.ca/~gambit/download/gambit/v4.6/prebuilt/gambc-v4_… http://www.iro.umontreal.ca/~gambit/download/gambit/v4.6/prebuilt/gambc-v4_… http://www.iro.umontreal.ca/~gambit/download/gambit/v4.6/prebuilt/gambc-v4_…

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Returning a symbol to scheme from C
by Alex Young 19 Fév '13

19 Fév '13

Hi there, I asked this question over on StackOverflow yesterday, but it's not had any joy so far. I've got a C function behind a c-lambda which needs to do some grubbing around with a select(2) call and decide on a scheme symbol to return as an indication of what it did, and whether an error condition occurred. Basically I want to use that symbol as a signal to drive a transition in a state machine. How one gets hold of a named symbol as a ___SCMOBJ (or anything more appropriate) from C isn't explained in the docs, and the wiki seems to have fallen over. It's also not immediately obvious from gambit.h whether there's a macro for this purpose. I've tried doing this: (define (foo) 'bar) and taking a look at the C it generates, but it looks to me like following this pattern only works if you know the offset into the symbol table in advance. Is this possible out of the box? My workaround at the moment is to pass in returnable symbols as arguments to the function, but with a larger set of symbols I want to be able to return, that's going to get very unwieldy very quickly. Thanks, -- Alex

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Mobile Scheme (Detroit)
by Jason Felice 19 Fév '13

19 Fév '13

Hi! I've been accepted to speak at MobiDevDay Detroit on "The Case for Scheme," May 4th. http://mobidevdaydetroit.com/ I'm hoping to advance some gambit for mobile stuff by then, but the talk is about Scheme as a DSL for cross-platform representation of business logic (e.g. back end/iOS/Android/Windows phone/etc.). I'd love to hook up with anyone who's working in this space there, whether as part of the conference or not. Thanks, -Jason

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