On Sun, Jun 19, 2011 at 1:32 PM, Stephen Blackheath [to GHC-iPhone] <likeliest.complexions.stephen@blacksapphire.com> wrote:

David,

In GHC-iPhone the number of function pointers that are allowed to be active for a given function is limited, but you can change the size of the limit. This is documented in

Steve,

Yep... I understand that there are not an unlimited number of function pointers. However, the function that I wrote was "supposed" to automatically release the function:

runOnMain :: IO () -> IO ()
runOnMain todo = do
                  func <- funky
                  dispatchFunc func
where funky = mkStrCB $ \v -> do
       todo

func <- funky
freeHaskellFunPtr func

Note the freeHaskellFunPtr function call at the end of the lambda.

I'm thinking that the "func <- funky" line is being treated as a recursive call and I'm also thinking that this is a limitation of my understanding the magic of lazy evaluation.

So, please let me rephrase my question:

How do I get the pointer to a wrapper function so that the pointer can be used within the wrapped function itself?

I have worked around the particular issue by making a call to freeHaskellFunPtr in the Objective-C code that invokes the function. It's less optimal that being able to have the Haskell code be able to auto-free the function pointer after the function is invoked.

Thanks,

David

http://projects.haskell.org/ghc-iphone/downloads/GHC-iPhone.pdf

on p5 under 'Pool sizes for foreign function "wrapper" callbacks'.

Steve

On 18/06/11 11:29, David Pollak wrote:

Howdy,

I tried to build a function that would create an auto-freeing function
pointer:

runOnMain :: IO () -> IO ()
runOnMain todo = do
func <- funky
dispatchFunc func
where funky = mkStrCB $ \v -> do
todo
func <- funky
freeHaskellFunPtr func

Unfortunately, I wind up getting:
internal error: iPhoneCreateAdjustor - adjustor pool 'Main_d2K2' is
empty (capacity 32)
(GHC version 6.10.4-iphone-simulator for i386_apple_darwin)

I'm not sure why, but I suspect that funky is being called recursively
and thus stuff is never being freed.

Any hints as to the issue and solutions?

Thanks,

David

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