September 2001 - Glasgow-haskell-users

Help in calling Haskell from C
by Mark Conway Wirt 12 Oct '01

12 Oct '01

I've been using hdirect for C <-> Haskell calls, and I've hit a bit of a snag. I'm using ghc 5.00.2 and hdirect 0.17. I've been able to call Haskell from C easily enough, but I've been unable to go the other way. I've tried following the directions in the hdirect manual, and tried building the examples in the hdirect distribution. Everything works up until final linking, where I receive undefined references. The C code should initialize the Haskell run-time, as it include the startup code: extern void startupHaskell (int argc, char* argv[]); startupHaskell(argc,argv); I'm compiling via ghc with the following options: ghc -package hdirect -fglasgow-exts -static -no-hs-main and the idl is compiled as such: ihc -s -fhs-to-c --gen-headers -fuse-ints-everywhere --output-h=.... Does hdirect work with ghc 5.00.2? I'm not receiving any errors in the build process, so I think my problems are more related to a lack of documentation, as opposed to a bug. Does anyone have any information (beyond what is in the hdirect documentation) on calling ghc-compiled code from C? The undefined references I'm getting are: undefined reference to `__init_Main' undefined reference to `Main_main_closure' Thanks in advance. I've looked though the mailing list archive and haven't found anything. If this has been answered before I apologize. --Mark

5 9

enormous binaries
by Willem Robert van Hage 02 Oct '01

02 Oct '01

Hello, I'm trying out GHC along with gtk+hs and iHaskell and I was surprised that a simple example with a list of selectable distribution names generated a binary of 2Mb. So I tried a simple hello world example exactly like the one I saw somewhere on the GHC pages that compiled to a binary of 6kb and I was surprised to see that even after stripping the binary it still takes up 140kb. Is there a good explanation for this? Am I doing something wrong or is it something else? ~/haskell/ghc-test % cat hello.hs module Main where main = putStrLn "hello, world!" ~/haskell/ghc-test % ghc -o hello hello.hs ~/haskell/ghc-test % ls -l total 212 -rwxr-xr-x 1 willem users 201453 Sep 29 09:55 hello -rw-r--r-- 1 willem users 51 Sep 29 09:54 hello.hs -rw-r--r-- 1 willem users 1468 Sep 29 09:55 hello.o ~/haskell/ghc-test % strip hello ~/haskell/ghc-test % ls -l total 152 -rwxr-xr-x 1 willem users 141024 Sep 29 09:59 hello -rw-r--r-- 1 willem users 51 Sep 29 09:54 hello.hs -rw-r--r-- 1 willem users 1468 Sep 29 09:55 hello.o ~/haskell/ghc-test % strings hello > strs I attached the file strs, maybe someone can deduce something from its contents... Willem van Hage -- wrvh(a)xs4all.nl | http://www.xs4all.nl/~wrvh wrvhage(a)science.uva.nl | http://quest.sourceforge.net

2 1

5.04 ?
by S.D.Mechveliani 29 Sep '01

29 Sep '01

Dear GHC, I have tested ghc-5.02 on various examples of computer algebra, with -O too. All tests are all right, except it shows a bug in memory management (Simon Marlow wrote of), visible in subtly chosen cases. The impression is that 5.02 saves much memory and gains performance in situations involving garbage collections (most practicable case). But due to the above bug, would 5.04 appear soon as a stable release? For I need to mention some newest stable GHC release in DoCon program documentation. Regards, ----------------- Serge Mechveliani mechvel(a)botik.ru

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Re: enormous executable
by S.D.Mechveliani 29 Sep '01

29 Sep '01

Willem Robert van Hage <wrvh(a)xs4all.nl> writes > [..] > So I tried a simple hello world example exactly like the one > I saw somewhere on the GHC pages that compiled to a binary of 6kb > and I was surprised to see that even after stripping the binary > it still takes up 140kb. > > -rwxr-xr-x 1 willem users 201453 Sep 29 09:55 hello > -rw-r--r-- 1 willem users 51 Sep 29 09:54 hello.hs > -rw-r--r-- 1 willem users 1468 Sep 29 09:55 hello.o It shows that source program takes 51 bytes, compiled object program - 1468 bytes. This is not mauch. Probably, the executable hello is 1000 times larger than object one because some piece of library (including binary code for outputting a string) is linked to it. In small user programs the library code is usually the larger part. In large user programs, it will be the smaller part. Regards, ----------------- Serge Mechveliani mechvel(a)botik.ru

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compiling hmake
by Colin Paul Adams 29 Sep '01

29 Sep '01

Can anyone tell me what options to pass to configure when trying to compile hmake with ghc 5.02? -- Colin Paul Adams Preston Lancashire

1 0

Telling ghc where to start
by George Russell 28 Sep '01

28 Sep '01

There are various reasons why one might have a Haskell file which doesn't have the expected "Module.hs" filename, in particular when putting ghc into some larger system which does its own thing with files. I may well want this as part of UniForM in the next few months. However ghc doesn't provide anyway support for this, and while you could create a symbolic link with a name ghc approves of to the real file, that seems somewhat messy. gcc has an option which allows you to specify that the input is, say, a C program (even though it's called "hello.txt") but it's rather messy and might take too long to implement. I suggest instead a new option called -virtual-name or something similar, so that ghc -virtual-name Module.hs /blah/horrible932 will compile the contents of /blah/horrible932, but treat it as if it were called "Module.hs".

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Happy 1.11 InstallShield released
by Reuben Thomas 28 Sep '01

28 Sep '01

A Happy 1.11 InstallShield is now available (including the post hoc bug fix!). -- http://sc3d.org/rrt/ | competent, a. underpromoted

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RE: Non blocking versions of hGetBuf and hPutBuf
by Simon Marlow 28 Sep '01

28 Sep '01

> Are they removed in GHC-5.02? Yes, I'm afraid so. I can implement them again for the new I/O library if necessary, but would it be possible for you to use the Posix library instead? Cheers, Simon

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Why have file names with 3 components?
by George Russell 28 Sep '01

28 Sep '01

This looks like a bug, but please don't change it! If you have a file A.blah.hs containing a module A, ghc5.02 compiles it, producing A.hi and A.blah.o. I have an application for this, since I have just, for the first time, been reluctantly compelled to introduce recursive modules. Rather than writing .hi-boot files (which might have to be rewritten for ghc5.03) I have instead written .boot.hs files, which yield .hi files, which then get moved to .hi-boot. Thus a module A has two sources, the real source A.hs, but also the source for the .hi-boot file, A.boot.hs.

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Non blocking versions of hGetBuf and hPutBuf
by Koen Claessen 28 Sep '01

28 Sep '01

Are they removed in GHC-5.02? /Koen

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