November 2005 - C2hs - Haskell.org

sizeof hook calculates the wrong size
by Volker Wysk 24 May '06

24 May '06

Hello The sizeof hook calculates the size wrong in this example: ----------------------------------------------------------------- main = putStrLn (show {# sizeof loop_info64_t #}) #c #include <linux/loop.h> typedef struct loop_info64 loop_info64_t; #endc ----------------------------------------------------------------- Translated to: ----------------------------------------------------------------- ... {-# LINE 1 "bug.chs" #-}main = putStrLn (show 72) ----------------------------------------------------------------- The structure is much larger. loop_info64 is defined in /usr/include/linux/loop.h like this: ----------------------------------------------------------------- struct loop_info64 { __u64 lo_device; /* ioctl r/o */ __u64 lo_inode; /* ioctl r/o */ __u64 lo_rdevice; /* ioctl r/o */ __u64 lo_offset; __u64 lo_sizelimit;/* bytes, 0 == max available */ __u32 lo_number; /* ioctl r/o */ __u32 lo_encrypt_type; __u32 lo_encrypt_key_size; /* ioctl w/o */ __u32 lo_flags; /* ioctl r/o */ __u8 lo_file_name[LO_NAME_SIZE]; __u8 lo_crypt_name[LO_NAME_SIZE]; __u8 lo_encrypt_key[LO_KEY_SIZE]; /* ioctl w/o */ __u64 lo_init[2]; }; ----------------------------------------------------------------- It looks like the the arrays are mistaken for pointers. There's another small bug. If you reorder main and the C block in the example above, such that "#c" is the first line, then you get a parse error. -- public key fingerprint: 6A10 66F1 40A2 C441 BB55 0AA8 FAB1 4FC1 08BE 24EF

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Pointers to structs without typedef
by Jelmer Vernooij 29 Nov '05

29 Nov '05

Hi, c2hs appears to have trouble with pointers to structs when not using typedefs. A simple that shows this behaviour: module Foo where #c struct foo { char x; }; void bar(struct foo *x); #endc {#pointer *'struct foo' as Foo newtype#} Am I doing something incorrectly or is this simply not supported? Cheers, Jelmer

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c2hs seems to ignore the types I give it when generating foreign import declarations
by Cale Gibbard 26 Nov '05

26 Nov '05

Hello, I've just started writing bindings to the Enlightenment Foundation Libraries, using c2hs. I've run into the following problem with the types in the foreign import declarations generated. In Imlib2.h, there is a function prototype: int imlib_get_visual_depth(Display * display, Visual * visual); In Imlib.chs, I have (among other things) import qualified Graphics.X11.Xlib.Types as Xlib -- ... {# fun imlib_get_visual_depth as getVisualDepth { id `Xlib.Display', id `Xlib.Visual' } -> `Int' #} I run: c2hs -k /usr/local/include/Imlib2.h Imlib.chs and in the resulting Imlib.hs, I get: --- this part is correct: getVisualDepth :: Xlib.Display -> Xlib.Visual -> IO (Int) getVisualDepth a1 a2 = let {a1' = id a1} in let {a2' = id a2} in getVisualDepth'_ a1' a2' >>= \res -> let {res' = cIntConv res} in return (res') --- this part is not: foreign import ccall safe "Imlib.h imlib_get_visual_depth" getVisualDepth'_ :: ((Ptr ()) -> ((Ptr ()) -> (IO CInt))) Why did it choose the type Ptr (), when I gave the type Xlib.Display? I could do an additional cast, but it will get tedious, as I have a lot of functions to import, and there shouldn't be any need for it anyway. As this is, it doesn't typecheck at all. If by hand, I change it to read: foreign import ccall safe "Imlib.h imlib_get_visual_depth" getVisualDepth'_ :: Xlib.Display -> Xlib.Visual -> IO CInt (which is what I expected it to produce in the first place) then it works as expected. Am I making a grievous error, or is this a bug/lack of a feature? - Cale

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.deb packages and problem in compilation
by Marco Tulio Gontijo e Silva 16 Nov '05

16 Nov '05

Hello, I'm packaging c2hs for debian, and the 0.13.6 packages are in the mirror, if you could add this in the website. Another thing is that I'm having a problem in compiling c2hs 0.14.3: marcot@tonhao:~/desenvolvimento/debian/c2hs$ tar xzf c2hs-0.14.3.tar.gz marcot@tonhao:~/desenvolvimento/debian/c2hs$ cd c2hs-0.14.3/ marcot@tonhao:~/desenvolvimento/debian/c2hs/c2hs-0.14.3$ ./Setup.hs configure Configuring c2hs-0.14.3... configure: Using install prefix: /usr/local configure: Using compiler: /usr/bin/ghc configure: Compiler flavor: GHC configure: Compiler version: 6.4.1 configure: Using package tool: /usr/bin/ghc-pkg configure: Using haddock: /usr/bin/haddock configure: No happy found configure: No alex found configure: Using hsc2hs: /usr/bin/hsc2hs configure: No c2hs found configure: No cpphs found configure: No greencard found checking build system type... i686-pc-linux-gnu checking host system type... i686-pc-linux-gnu checking for gcc... gcc checking for C compiler default output file name... a.out checking whether the C compiler works... yes checking whether we are cross compiling... no checking for suffix of executables... checking for suffix of object files... o checking whether we are using the GNU C compiler... yes checking whether gcc accepts -g... yes checking for gcc option to accept ANSI C... none needed checking how to run the C preprocessor... gcc -E checking for egrep... /bin/egrep checking for sed... /bin/sed configure: creating ./config.status config.status: creating c2hs/toplevel/Version.hs config.status: creating c2hs/toplevel/C2HSConfig.hs config.status: creating c2hs/c2hs-inplace config.status: creating c2hs/c2hs config.status: creating postInst.sh config.status: creating c2hs.spec config.status: creating doc/c2hs/Makefile config.status: executing default commands marcot@tonhao:~/desenvolvimento/debian/c2hs/c2hs-0.14.3$ ./Setup.hs build Preprocessing executables for c2hs-0.14.3... Building c2hs-0.14.3... Chasing modules from: c2hs/toplevel/Main.hs Could not find module `CForeign': use -v to see a list of the files searched for (imported from c2hs/toplevel/C2HSConfig.hs) marcot@tonhao:~/desenvolvimento/debian/c2hs/c2hs-0.14.3$ Do you know what is the problem here? -- Abraços, marcot mailto:marcot@minaslivre.org jabber:marcott@jabber.org UIN:50599075 MSN:marcot@ufmg.br Telefone:33346720 Celular:91844179 Endereço:Rua Paula Cândido 257/201 Gutierrez 30430-260 Belo Horizonte-MG Brasil

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Accessing an array inside a structure
by Volker Wysk 12 Nov '05

12 Nov '05

Hello There appears to be a bug. Accessing a member array of a C structure via a get hook, produces a pointer read off the array, instead of a pointer to the array: test.chs----------------------------------------- #c typedef struct { char str[10]; } t; t x = { "blah" }; #endc foo = {# get t.str #} ------------------------------------------------- Translates to: test.hs------------------------------------------ ... foo = (\ptr -> do {peekByteOff ptr 0 ::IO (Ptr CChar)}) ... ------------------------------------------------- Regards, V.W. -- public key fingerprint: 6A10 66F1 40A2 C441 BB55 0AA8 FAB1 4FC1 08BE 24EF

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.deb packages and problem in compilation
by Marco Tulio Gontijo e Silva 09 Nov '05

09 Nov '05

Hello, I'm packaging c2hs for debian, and the 0.13.6 packages are in the mirror, if you could add this in the website. Another thing is that I'm having a problem in compiling c2hs 0.14.3: marcot@tonhao:~/desenvolvimento/debian/c2hs$ tar xzf c2hs-0.14.3.tar.gz marcot@tonhao:~/desenvolvimento/debian/c2hs$ cd c2hs-0.14.3/ marcot@tonhao:~/desenvolvimento/debian/c2hs/c2hs-0.14.3$ ./Setup.hs configure Configuring c2hs-0.14.3... configure: Using install prefix: /usr/local configure: Using compiler: /usr/bin/ghc configure: Compiler flavor: GHC configure: Compiler version: 6.4.1 configure: Using package tool: /usr/bin/ghc-pkg configure: Using haddock: /usr/bin/haddock configure: No happy found configure: No alex found configure: Using hsc2hs: /usr/bin/hsc2hs configure: No c2hs found configure: No cpphs found configure: No greencard found checking build system type... i686-pc-linux-gnu checking host system type... i686-pc-linux-gnu checking for gcc... gcc checking for C compiler default output file name... a.out checking whether the C compiler works... yes checking whether we are cross compiling... no checking for suffix of executables... checking for suffix of object files... o checking whether we are using the GNU C compiler... yes checking whether gcc accepts -g... yes checking for gcc option to accept ANSI C... none needed checking how to run the C preprocessor... gcc -E checking for egrep... /bin/egrep checking for sed... /bin/sed configure: creating ./config.status config.status: creating c2hs/toplevel/Version.hs config.status: creating c2hs/toplevel/C2HSConfig.hs config.status: creating c2hs/c2hs-inplace config.status: creating c2hs/c2hs config.status: creating postInst.sh config.status: creating c2hs.spec config.status: creating doc/c2hs/Makefile config.status: executing default commands marcot@tonhao:~/desenvolvimento/debian/c2hs/c2hs-0.14.3$ ./Setup.hs build Preprocessing executables for c2hs-0.14.3... Building c2hs-0.14.3... Chasing modules from: c2hs/toplevel/Main.hs Could not find module `CForeign': use -v to see a list of the files searched for (imported from c2hs/toplevel/C2HSConfig.hs) marcot@tonhao:~/desenvolvimento/debian/c2hs/c2hs-0.14.3$ Do you know what is the problem here? Please CC to me, I'm not on the list. -- Abraços, marcot mailto:marcot@minaslivre.org jabber:marcott@jabber.org UIN:50599075 MSN:marcot@ufmg.br Telefone:33346720 Celular:91844179 Endereço:Rua Paula Cândido 257/201 Gutierrez 30430-260 Belo Horizonte-MG Brasil

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