ah ..,. right ,..... my bad. Vasili On Sun, Jun 8, 2008 at 10:01 PM, Luke Palmer wrote:

2008/6/8 Galchin, Vasili :

...

Hello,

I am getting what is to me a mysterious error in a test case that I am writing: vigalchin@ubuntu:~/FTP/Haskell/unix-2.2.0.0/tests/timer$ runhaskell Setup.lhs build Preprocessing executables for Test-1.0... Building Test-1.0... [1 of 1] Compiling Main ( ./timer.hs, dist/build/timer/timer-tmp/Main.o )

./timer.hs:11:45: Not in scope: data constructor `FunPtr'

There is a *type* called FunPtr in scope, but not a data constructor as you are using it. That is, you could say:

foo :: FunPtr (Int -> IO ())

That is, use the type called FunPtr, but you may not use a *function* called FunPtr, because it doesn't exist. You need to use functions like nullFunPtr, castPtrToFunPtr, etc. to construct FunPtrs.

Luke

Thanks. Clause? regards, Vasili On Mon, Jun 9, 2008 at 12:54 AM, Bulat Ziganshin wrote:

Hello Vasili,

Monday, June 9, 2008, 6:17:14 AM, you wrote:

1. standard place to import FunPtr from is Foreign.Ptr, not System.Posix 2. FunPtr is exported as abstract type, without constructors. you can't construct values of this type directly. instead you should use "wrapper" generators as in the example that Clause has wrote. read it carefully :)

...

Hello,

...

I am getting what is to me a mysterious error in a test case that I

am writing:

...

vigalchin@ubuntu:~/FTP/Haskell/unix-2.2.0.0/tests/timer$ runhaskell Setup.lhs build Preprocessing executables for Test-1.0... Building Test-1.0... [1 of 1] Compiling Main ( ./timer.hs, dist/build/timer/timer-tmp/Main.o )

...

./timer.hs:11:45: Not in scope: data constructor `FunPtr'

...

It seems like the compiler is complaining about the lack of FunPtr in it's symbol table but System.Posix is imported:

module Main where

...

import System.Posix import Foreign import Foreign.C import Foreign.Ptr

...

main = do

...

let event = Sigevent{sigevFunction=(FunPtr (notifyFunc))}

<<<<<< error here

...

timerId <- timerCreate Clock_Realtime Nothing

...

timerDelete timerId

...

return ()

...

notifyFunc :: Sigval -> IO () notifyFunc sigval = do putStrLn "timer POP!!!!!!!" return ()

...

I am probably looking right at the answer and not seeing it. ??

...

Thanks, Vasili

...

-- Best regards, Bulat mailto:Bulat.Ziganshin@gmail.com

type Notify = Sigval -> IO () foreign import ccall "wrapper" mkNotify :: Notify -> IO (FunPtr Notify)

then

main = do notifyFPtr <- mkNotify notifyFunc -- rest of code here

-- then, when you are done and nothing is referencing the pointer any more freeHaskellFunPtr notifyFPtr

On 6/9/08, Galchin, Vasili wrote:

In any case, what I want to do is store FunPtr in a data type and marshall into a C struct as a C function pointer.

Vasili

This will be suitable for that purpose. -- ryan

2008/6/9 Galchin, Vasili :

Ryan,

I tried but the compiler didn't seem to like the keyword "import":

vigalchin@ubuntu:~/FTP/Haskell/unix-2.2.0.0/tests/timer$ runhaskell Setup.lhs build Preprocessing executables for Test-1.0... Building Test-1.0... [1 of 1] Compiling Main ( ./timer.hs, dist/build/timer/timer-tmp/Main.o )

./timer.hs:29:8: parse error on input `import'

Hi Vasili, To fix that error, you probably just need to add the line "Extensions: ForeignFunctionInterface" to the .cabal file. (That is the equivalent of calling ghc by itself with the command-line arguments -fffi or -XForeignFunctionInterface.) Hope that helps, -Judah

I have tried various things to no avail .... vigalchin@ubuntu:~/FTP/Haskell/unix-2.2.0.0/tests/timer$ runhaskell Setup.lhs build Preprocessing executables for Test-1.0... Building Test-1.0... [1 of 1] Compiling Main ( ./timer.hs, dist/build/timer/timer-tmp/Main.o ) ./timer.hs:22:0: Unacceptable argument type in foreign declaration: Sigval When checking declaration: foreign import ccall safe "wrapper" mkNotify :: Notify -> IO (FunPtr Notify) => here is my Sigval def data Sigval = SivalInt Int | SivalPtr (Ptr Char) I did a find/grep for "Unacceptable argument" in the ghc compiler source and assuming no typo I didn't find. ?? Thanks. Kind regards, Vasili On Mon, Jun 9, 2008 at 11:25 PM, Judah Jacobson wrote:

2008/6/9 Galchin, Vasili :

...

Ryan,

I tried but the compiler didn't seem to like the keyword "import":

vigalchin@ubuntu:~/FTP/Haskell/unix-2.2.0.0/tests/timer$ runhaskell Setup.lhs build Preprocessing executables for Test-1.0... Building Test-1.0... [1 of 1] Compiling Main ( ./timer.hs, dist/build/timer/timer-tmp/Main.o )

./timer.hs:29:8: parse error on input `import'

Hi Vasili,

To fix that error, you probably just need to add the line "Extensions: ForeignFunctionInterface" to the .cabal file. (That is the equivalent of calling ghc by itself with the command-line arguments -fffi or -XForeignFunctionInterface.)

Hope that helps, -Judah

Also, if you always plan to partially apply your notification function and you just want a simple callback: void (*pCallbackFn)(void); You should be able to do something like this:

type Callback = IO () foreign import ccall "wrapper" mkCallback :: Callback -> IO (FunPtr Callback)

You can then do something like

main = do let event = Sigval { ... fill in here ... } callback <- mkCallback (notify event) ... freeHaskellFunPtr callback

On 6/10/08, Ryan Ingram wrote:

I'm not super experienced with the FFI (foreign function interface); I only used C types that you can get from #include , like Word32.

You might need to make Sigval an instance of Storable, or do some magic with ForeignPtrs. Good luck! :)

-- ryan

On 6/9/08, Galchin, Vasili wrote:

...

I have tried various things to no avail ....

vigalchin@ubuntu:~/FTP/Haskell/unix-2.2.0.0/tests/timer$ runhaskell Setup.lhs build Preprocessing executables for Test-1.0... Building Test-1.0... [1 of 1] Compiling Main ( ./timer.hs, dist/build/timer/timer-tmp/Main.o )

./timer.hs:22:0: Unacceptable argument type in foreign declaration: Sigval When checking declaration: foreign import ccall safe "wrapper" mkNotify :: Notify -> IO (FunPtr Notify)

=> here is my Sigval def

data Sigval = SivalInt Int | SivalPtr (Ptr Char)

I did a find/grep for "Unacceptable argument" in the ghc compiler source and assuming no typo I didn't find. ??

Thanks.

Kind regards, Vasili

On Mon, Jun 9, 2008 at 11:25 PM, Judah Jacobson wrote:

...

2008/6/9 Galchin, Vasili :

...

Ryan,

I tried but the compiler didn't seem to like the keyword "import":

vigalchin@ubuntu:~/FTP/Haskell/unix-2.2.0.0/tests/timer$ runhaskell

...

Setup.lhs build Preprocessing executables for Test-1.0... Building Test-1.0... [1 of 1] Compiling Main ( ./timer.hs, dist/build/timer/timer-tmp/Main.o )

./timer.hs:29:8: parse error on input `import'

Hi Vasili,

To fix that error, you probably just need to add the line "Extensions: ForeignFunctionInterface" to the .cabal file. (That is the equivalent of calling ghc by itself with the command-line arguments -fffi or -XForeignFunctionInterface.)

Hope that helps, -Judah

oops .. my bad ... If I change data Sigval = SivalInt Int to newtype Sigval = SivalInt Int OR data Sigval = SivalPtr (Ptr Char) to newtype Sigval = SivalPtr (Ptr Char). Why should "newtype" instead of a data type allow my test case to build? Vasili On Fri, Jun 13, 2008 at 10:59 PM, Galchin, Vasili wrote:

If I change

data Sigval = SivalInt Int | SivalPtr (Ptr Char) to ...

newtype Sigval = Sivalint Int | SivalPtr (Ptr Char)

then my test case builds and links. ??

Regards, Vasili

On Mon, Jun 9, 2008 at 11:01 PM, Galchin, Vasili wrote:

...

I have tried various things to no avail ....

vigalchin@ubuntu:~/FTP/Haskell/unix-2.2.0.0/tests/timer$ runhaskell Setup.lhs build Preprocessing executables for Test-1.0... Building Test-1.0... [1 of 1] Compiling Main ( ./timer.hs, dist/build/timer/timer-tmp/Main.o )

./timer.hs:22:0: Unacceptable argument type in foreign declaration: Sigval When checking declaration: foreign import ccall safe "wrapper" mkNotify :: Notify -> IO (FunPtr Notify)

=> here is my Sigval def

data Sigval = SivalInt Int | SivalPtr (Ptr Char)

I did a find/grep for "Unacceptable argument" in the ghc compiler source and assuming no typo I didn't find. ??

Thanks.

Kind regards, Vasili

On Mon, Jun 9, 2008 at 11:25 PM, Judah Jacobson < judah.jacobson@gmail.com> wrote:

...

2008/6/9 Galchin, Vasili :

...

Ryan,

I tried but the compiler didn't seem to like the keyword "import":

vigalchin@ubuntu:~/FTP/Haskell/unix-2.2.0.0/tests/timer$ runhaskell Setup.lhs build Preprocessing executables for Test-1.0... Building Test-1.0... [1 of 1] Compiling Main ( ./timer.hs, dist/build/timer/timer-tmp/Main.o )

./timer.hs:29:8: parse error on input `import'

Hi Vasili,

To fix that error, you probably just need to add the line "Extensions: ForeignFunctionInterface" to the .cabal file. (That is the equivalent of calling ghc by itself with the command-line arguments -fffi or -XForeignFunctionInterface.)

Hope that helps, -Judah