Re: [C2hs] help a newbie?

Eric Sessoms:

Followup: is there any way to specify a default marshaller? For example, is there a way to specify in one place "always use withFitsFile* to marshal a FitsFile" (or similar)?

That would be useful, but like with default marshallers for pointer hooks, it is not currently implemented. Manuel

On 2/22/07, Duncan Coutts wrote:

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On Tue, 2007-02-20 at 20:40 -0500, Eric Sessoms wrote:

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I'm working on a problem that looks, to my eye, identical to the example in section 2.10 of the documentation http://www.cse.unsw.edu.au/~chak/haskell/c2hs/docu/c2hs-2.html#ss2.10

--- cut here --- module Test where

#c typedef struct { int dummy; } fitsfile;

int ffclos(fitsfile *fptr, int *status); #endc

{# pointer *fitsfile as FitsFile newtype #}

{# fun ffclos { `FitsFile', `Int' } -> `Int' #} --- cut here --

But running c2hs I get an error message that I haven't been able to make use of:

Test.chs:13: (column 17) [ERROR]

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Missing "in" marshaller! There is no default marshaller for this combination of Haskell and C type: Haskell type: FitsFile C type : (FitsFile)

I'm not sure if c2hs is supposed to work out the default marshaler automatically, you'd have to ask Manuel, but it does work if you specify the marshaler explicitly:

{# fun ffclos { withFitsFile `FitsFile', `Int' } -> `Int' #}

Duncan