Gambit-list Octobre 2011

gambit-list@iro.umontreal.ca

22 participants
27 discussions

Edge triggered I/O with libevent
by Adam Langley 04 Avr '13

04 Avr '13

Gambit uses the select call on POSIX systems to multiplex IO operations. This is fine for small numbers of file descriptors, but falls apart quickly with large numbers[1]. libevent[2] is a wrapper library around a number of modern IO multiplexing systems (epoll on Linux, kqueue on the BSDs as well as poll and select). Attached is a patch which converts Gambit to using edge triggered I/O with epoll and libevent. This also requires a patch (attached) of libevent since the standard distribution doesn't include edge triggering support and the upstream appears to be on holiday. (epoll is required because I don't have a BSD box on which to develop edge triggering support for kqueue) This patch (for Gambit) preprocesses away to nothing unless --enable-libevent is passed to the configure script. (Note that, since this patches the configure.ac script, you'll need to run autoconf to regenerate). I hope I've not broken anything, but at this stage I've only tested that the console and tcp ports work. This patch (in the future) should also allow people, who write programs which use socket calls directly, to integrate into the main event loop at some point. Testing is more than welcome and, if you find a form of IO which is broken, please email me. [1] http://monkey.org/~provos/libevent/libevent-benchmark2.jpg [2] http://monkey.org/~provos/libevent/ -- Adam Langley agl(a)imperialviolet.org http://www.imperialviolet.org (+44) (0)7906 332512 PGP: 9113 256A CC0F 71A6 4C84 5087 CDA5 52DF 2CB6 3D60

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How to ue a module?
by Hendrik Boom 25 Jan '12

25 Jan '12

I just made bootstrap from the 4.6.1 development sources, which I downloaded using git. When I start gsi and, according to the section "Subdivide code into modules" in the tour of Scheme in Gambit, I use "use" it tells me hendrik@notlookedfor:~/dv/lang/gambit/gambit$ gsi/gsi Gambit v4.6.1 > (use ssax-sxml) *** ERROR IN (console)(a)1.2 -- Unbound variable: use 1> So evidently something is still missing, unconfigured, unbuilt, or whatever. It doesn't even get around to looking for the library -- which is another question: how does it find the libraries, assuming it gets that far. And if the X module system is itself a module, how do I bootstrap it into the system? Or should I be using an entirely different mechanism? -- hendrik

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Ill formed expression
by Vok Vojwo 10 Nov '11

10 Nov '11

I get the error Ill-formed expression for this syntax definition: (define-syntax ? (syntax-rules () ((? arg) (let ((val arg)) (display "+++ ") (write 'arg) (display ": ") (write val) (newline) val)))) Can anybody tell me what is wrong? Guile accepts the definition.

4 5

Error when loading/running
by Steve Graham 31 Oct '11

31 Oct '11

Newbie here. I'm trying to run a scheme program from gsi and getting an error I don't understand: C:\gambit\gambitv4.6.2\v4.6.2\bin>type timecalc.sch (define hrs1) (define hrs2) (display "Hrs 1: ") (set! hrs1 (read)) (display "\nHrs 2: ") (set! hrs2 (read)) (print "\n\n" (+ hrs1 hrs2) " hours --> $" (* (+ hrs1 hrs2) 22))' C:\gambit\gambitv4.6.2\v4.6.2\bin>gsi -:d0 timecalc.sch C:\gambit\gambitv4.6.2\v4.6.2\bin>gsi timecalc.sch *** ERROR IN "timecalc.sch"@7.1 -- Datum expected C:\gambit\gambitv4.6.2\v4.6.2\bin>gsi Gambit v4.6.2 > (load "timecalc.sch") *** ERROR IN "timecalc.sch"@7.1 -- Datum expected 1> Any tips? TIA, Steve

3 4

Re: [gambit-list] How thread-mailbox-extract-without-rewind
by Vok Vojwo 31 Oct '11

31 Oct '11

Am 31.10.2011 12:27 schrieb "Adrien Piérard" <pierarda(a)iro.umontreal.ca>: > > What about using queues > > Doesn't this solve your problem? Yes but you see it is much code. It is only necessary, because I can not decrement the inbox message cursor.

1 0

How thread-mailbox-extract-without-rewind
by Vok Vojwo 31 Oct '11

31 Oct '11

I would like to remove the last message read from a thread mailbox by thread-mailbox-next without rewinding the message cursor. How can I do that?

2 4

For fork:ed Gambit process that should not take any console input, how uninitialize stdin & signal handlers? (Possibly only needed to be done for the handler for SIGTSTP.)
by Mikael 29 Oct '11

29 Oct '11

Hi, making a strace wrapper app monitor to be run in a fork:ed Gambit process. This process is completely silent and never has any console interaction except for minor output to stdout. In the current setup, when I press ctrl+c, both forked processes respond with getting to the REPL. For the fork:ed process that should not have any console interaction anymore, how do I disable this behavior i.e. how do I shut down signal handlers & stdin for it? (Possibly only needed to be done for the handler for SIGTSTP.) I tried doing (close-port (current-input-port)) but it didn't deliver for this purpose. Kind regards, Mikael

1 1

Gambit on Windows with Emacs
by Vok Vojwo 29 Oct '11

29 Oct '11

I tried to run gsi as the Emacs scheme interpreter on Windows. So I set scheme-program-name to "C:/Progra~2/Gambit-C/v4.6.2/bin/gsi -:t". But Emacs does not show the repl, because the gsi.exe seems to be a Windows program which always starts a new window. Is there a gsi version available which will run in the current terminal without starting a new window? I installed the latest Gambit Ming package.

2 4

Re: [gambit-list] Gambit on Windows with Emacs
by Vok Vojwo 29 Oct '11

29 Oct '11

2011/10/29 Dominique Boucher <schemeway(a)gmail.com>: > try starting gsi with the -:d- option. This way, gsi is controlled using > standard input and output. Thanks! That works on Windows, too.

1 0

Is (void) distinct from all other types?
by Vok Vojwo 28 Oct '11

28 Oct '11

Is (void) distinct from all other types? Is this a proper way to check if anything is undefined? (let () (define a) (eq? a (void))) I think (define a) does not conform to RnRS, because define requires two arguments. Is there a RnRS conforming way to check if anything is undefined/unspecified?

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Gambit-list Octobre 2011