September 2001 - Glasgow-haskell-users

Re: Exporting a String
by Marcin 'Qrczak' Kowalczyk 28 Sep '01

28 Sep '01

Fri, 28 Sep 2001 08:20:08 +0200, Sven Eric Panitz <sep(a)softwareag.com> pisze: > xs <- peekCString cxs > ys <- peekCString cys > erg <- return (xs++ys) The last line can be written: let erg = xs++ys and you can also directly write (xs++ys) instead of erg below. > newCString erg All OK, except that you leak memory. This string is allocated using malloc and should be freed using free when no longer needed (either C free or Haskell free). > //calling Haskell function > test=cAppend("the world"," is my oyster"); > > //printing its result > printf("%s\n", test); And then: free(test); BTW, there is less boilerplate (no startupHaskell etc.) when the main program is in Haskell instead of C (of course sometimes this is not what we want). -- __("< Marcin Kowalczyk * qrczak(a)knm.org.pl http://qrczak.ids.net.pl/ \__/ ^^ SYGNATURA ZASTÊPCZA QRCZAK

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More 5.02 downloads
by Reuben Thomas 28 Sep '01

28 Sep '01

I've updated the 5.02 Windows InstallShield, getting rid of one or two teething problems, and improving the availability of the docs. I've also added links to the RedHat 7.1 RPMs and FreeBSD/x86 binary dist. http://www.haskell.org/ghc/download_ghc_502.html is the hot destination. -- http://sc3d.org/rrt/ L'art des vers est de transformer en beautés les faiblesses (Aragon)

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Re: Exporting a String
by Sven Eric Panitz 28 Sep '01

28 Sep '01

I am no expert in these things, but as a matter of fact I just did some quite similar and found the help in the mailing list archive. (at least I did not find a cookbook for this in the documentation) My Haskell module: ================== module Mini where import CString foreign export stdcall cAppend :: CString -> CString -> IO CString cAppend :: CString -> CString -> IO CString cAppend cxs cys = do xs <- peekCString cxs ys <- peekCString cys erg <- return (xs++ys) newCString erg And my C program Main.c calling this function: ============================================== #include <stdio.h> #include "Mini_stub.h" #include "RtsAPI.h" extern void __stginit_Mini ( void ); int main(void) { char* bogusFlags[1] = { "\0" }; char* test; //starting up Haskell runtime startupHaskell(0, bogusFlags, __stginit_Mini); //calling Haskell function test=cAppend("the world"," is my oyster"); //printing its result printf("%s\n", test); //say bye bye to Haskell shutdownHaskell(); return 0; } and my way to build this thing: =============================== ghc -fglasgow-exts -package text -c Mini.hs gcc -I. -I'e:/Program Files/ghc/ghc-5.02/include' -I'E:\Program Files\ghc\ghc-5.02\include\mingw' -c Main.c ghc -fglasgow-exts -no-hs-main -package text -static Main.o Mini.o Mini_stub.o -o Test.exe Please some expert correct me, if this is not the right way to do this. Sven Eric -- ______________________________________________________________ Sven Eric Panitz Uhlandstr. 12 D-64297 Darmstadt Software AG sep(a)softwareag.com (+49)6151-92-1426 --- when I cannot sing my heart, I can only speak my mind ---

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RE: Cash Prizes Win!
by Ashley Yakeley 27 Sep '01

27 Sep '01

At 2001-09-27 03:48, Simon Marlow wrote: >I could turn on subscriber-only posting if there's a consensus to do >that. I vote for that. >It might be inconvenient in that you have to post from the same >account that you read Haskell mail from though, and I know some people >have separate email accounts just for receiving Haskell mail. I also run an email list using Mailman. Anytime a subscriber sends a message from a 'wrong' address, Mailman catches it, and I simply subscribe that address 'nomail', and approve the message. >Also, what do people think about the volume of Conference-related >announcements sent to the list (haskell(a)haskell.org in particular)? I'm not really bothered by the way it is... -- Ashley Yakeley, Seattle WA

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Exporting a String
by Juan Ignacio García García 27 Sep '01

27 Sep '01

hello, Is there any way to export a value of type String? I have tried it as follows Haskell code foreign export f::Int -> IO (StablePtr String) f:: Int -> IO (StablePtr String) f n = newStablePtr ("hola") C code char *cad; cad=f(5); printf("%s",cad); but it does not go (segmentation fault). Thanks in advance, J. Ignacio García

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packages in ghci
by Sven Eric Panitz 27 Sep '01

27 Sep '01

I just downloaded the nice installation of ghc 5.02 for windows. I have just some problem when trying to start ghci with a package as described in the manual: > E:\hs\Quip>ghci -package text > e:\PROGRA~1\ghc\ghc-5.02\bin\ghc.exe: no input files > Usage: For basic information, try the `--help' option. > > E:\hs\Quip> Adding a Haskell source file as further parameter does not really help: > E:\hs\Quip>ghci -package text M.hs > A' does not existhc-5.02\bin\ghc.exe: file `= > > E:\hs\Quip> Any idea, what I am doing wrong? Sven Eric -- ______________________________________________________________ Sven Eric Panitz Uhlandstr. 12 D-64297 Darmstadt Software AG sep(a)softwareag.com (+49)6151-92-1426 --- when I cannot sing my heart, I can only speak my mind ---

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RE: Cash Prizes Win!
by Simon Marlow 27 Sep '01

27 Sep '01

[ Ketil Malde asks about recent spam on Haskell mailing lists... ] > How about disallowing non-subscribers from posting? This list is my > main source of spam these days. (Effective filtering is your friend) My apologies for this spam that got through. Mailman's automatic filtering catches *most* of the spam bound for the list - there are usually a few messages per day. The ones that get through are very much the exception, but it does occasionally happen. I could turn on subscriber-only posting if there's a consensus to do that. It might be inconvenient in that you have to post from the same account that you read Haskell mail from though, and I know some people have separate email accounts just for receiving Haskell mail. What do people think? Also, what do people think about the volume of Conference-related announcements sent to the list (haskell(a)haskell.org in particular)? Most of these get caught by the filter, and I tend to disallow only those that have no connection to programming language research at all. This could be tightened to Haskell-related or functional programming-related conferences only. Cheers, Simon

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Cash Prizes Win!
by Claire 27 Sep '01

27 Sep '01

To all our fans!! Welsh Fantasy Football has paid your entrance fee to the WELSH FANTASY FOOTBALL GAME 2001 Go to www.welshfantasyfootball.com you have to be in it to WIN it!!

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RE: extra_ghc_opts syntax
by Alex Ferguson 26 Sep '01

26 Sep '01

> Just write the list twice, once with the quotes and commas and once > without? Alternative I guess you could try to transform one into the > other using sed, perl, python, etc. but I would just do it the easy way. Doesn't everyone on this list use Haskell for their string-processing, then? ;-) (This one is about a one-liner...) Cheers, Alex.

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FreeBSD binary distribution of 5.02 available
by Simon Marlow 26 Sep '01

26 Sep '01

There's a FreeBSD binary dist, for 4.4-STABLE, here: http://www.haskell.org/ghc/dist/5.02/ghc-5.02-i386-unknown-freebsd.tar.g z This is just a standard .tar.gz binary dist, not a package, for now. I'm currently updating the port for 5.02, but I think this time I'm going to make it bootstrap from the pre-built binary distribution rather than from HC files. The HC file route is too error-prone (and it takes longer, too). I checked the other ports, and it seems this is the way they do the GNAT port too. Cheers, Simon

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