July 2012 - C2hs - Haskell.org

[c2hs] #39: language-c-0.4.2.0 compatibility
by c2hs 09 Feb '13

09 Feb '13

#39: language-c-0.4.2.0 compatibility --------------------+------------------------------------------------------- Reporter: guest | Type: defect Status: new | Priority: normal Milestone: | Component: general Version: 0.16.2 | Keywords: --------------------+------------------------------------------------------- Hi, for Debian, I patched c2hs to build against the language-c in the latest version. The patch is purely type-driven, and not checked against possible changes in the semantics of language-c. Thanks, Joachim -- Ticket URL: <http://hackage.haskell.org/trac/c2hs/ticket/39> c2hs <http://www.cse.unsw.edu.au/~chak/haskell/c2hs/> C->Haskell, An Interface Generator for Haskell

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[c2hs] #42: Nonstandard binary installation directory
by c2hs 09 Feb '13

09 Feb '13

#42: Nonstandard binary installation directory --------------------+------------------------------------------------------- Reporter: guest | Type: defect Status: new | Priority: normal Milestone: | Component: general Version: 0.16.0 | Keywords: --------------------+------------------------------------------------------- c2hs doesn't install in the proper directory ({{{ ~/.cabal/bin }}}). Instead, it installs in {{{ /Users/andrew/Library/Haskell/ghc-7.0.3/lib/c2hs-0.16.3/bin }}}. This creates problems with subsequent packages which depend on c2hs's installation and inclusion in {{{ PATH }}}. -- Ticket URL: <http://hackage.haskell.org/trac/c2hs/ticket/42> c2hs <http://www.cse.unsw.edu.au/~chak/haskell/c2hs/> C->Haskell, An Interface Generator for Haskell

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[c2hs] #48: Interpreted an int64_t typedef as CInt
by c2hs 05 Jul '12

05 Jul '12

#48: Interpreted an int64_t typedef as CInt --------------------+------------------------------------------------------- Reporter: guest | Type: defect Status: new | Priority: blocker Milestone: | Component: general Version: 0.16.2 | Keywords: --------------------+------------------------------------------------------- A library I'd like to write bindings to has a typedef of int64_t to a library-specific type name. c2hs seems to interpret that type as CInt, both in foreign import declarations and in {# type #} directives. It should interpret that type as a 64-bit integer type instead. -- Ticket URL: <http://hackage.haskell.org/trac/c2hs/ticket/48> c2hs <http://www.cse.unsw.edu.au/~chak/haskell/c2hs/> C->Haskell, An Interface Generator for Haskell

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[c2hs] #47: Void functions produce a "defined but not used" warning for the result
by c2hs 05 Jul '12

05 Jul '12

#47: Void functions produce a "defined but not used" warning for the result --------------------+------------------------------------------------------- Reporter: guest | Type: defect Status: new | Priority: normal Milestone: | Component: general Version: 0.16.0 | Keywords: --------------------+------------------------------------------------------- Declaring a {# fun ... #} with return type `()' leads to the following warning from GHC: Warning: Defined but not used: `res' Please consider either using res or declaring it as _ in this case, to prevent the warning. -- Ticket URL: <http://hackage.haskell.org/trac/c2hs/ticket/47> c2hs <http://www.cse.unsw.edu.au/~chak/haskell/c2hs/> C->Haskell, An Interface Generator for Haskell

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[c2hs] #46: No way to create a foreign pointer for input and have it as an out parameter
by c2hs 05 Jul '12

05 Jul '12

#46: No way to create a foreign pointer for input and have it as an out parameter --------------------+------------------------------------------------------- Reporter: guest | Type: defect Status: new | Priority: normal Milestone: | Component: general Version: 0.16.0 | Keywords: --------------------+------------------------------------------------------- I have quite a few C functions like this: ... func(oid *, ...); oid refers to a non-opaque C struct, and these functions treat it as an out parameter; a C caller would define an instance of the struct (knowing its size) and pass the address of that structure to have it filled in. I'd like to allocate memory for this struct using mallocForeignPtrBytes {# sizeof oid #}, pass the underlying Ptr to the function, and then return the foreign pointer wrapped in an opaque type (defined using {# pointer ... foreign newtype #}). Note that the documentation for mallocForeignPtrBytes specifically says that GHC implements it much more efficiently than a standard ForeignPtr with a finalizer of finalizerFree; otherwise, I could just use malloc and then wrap the pointer on the way out. As far as I can tell, a {# fun ... #} wrapper cannot implement this pattern. Any output marshaller has to work using the same value passed to the function, which in this case would be a Ptr, not a ForeignPtr. Thus, I can't both create an OID in the input marshaller (using a - so the caller doesn't have to pass one) and return that OID from the function. At the moment, I've come up with three workarounds, none of which work very well: - Write a {# fun ... #} wrapper using withOID* and write a Haskell wrapper function that calls newOID first, requiring an extra five lines for every function using an OID. - Give up on mallocForeignPtrBytes and use malloc on input and newForeignPtr on output, with resulting inefficiency (the library uses a *lot* of these structures). - Use alloca on input, and have the output marshaller use mallocForeignPtrBytes and make a copy. Efficient use of memory and efficient reclamation, but an extra copy per call. Ideally, I'd prefer to have a way to declare this pattern directly in a marshaller. I'd suggest adding a new symbol to apply to the input marshaller, which allows it to provide an output directly. -- Ticket URL: <http://hackage.haskell.org/trac/c2hs/ticket/46> c2hs <http://www.cse.unsw.edu.au/~chak/haskell/c2hs/> C->Haskell, An Interface Generator for Haskell

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[c2hs] #45: Please indent all output lines from a {# fun ... #} to match the input indentation, to allow it in a where clause
by c2hs 05 Jul '12

05 Jul '12

#45: Please indent all output lines from a {# fun ... #} to match the input indentation, to allow it in a where clause --------------------+------------------------------------------------------- Reporter: guest | Type: defect Status: new | Priority: normal Milestone: | Component: general Version: 0.16.0 | Keywords: --------------------+------------------------------------------------------- I tried to declare a {# fun ... #} in a where clause, but only the first line had the proper indentation, causing GHC to complain that "The type signature for `foo' lacks an accompanying binding" (because only the type signature appeared within the where clause). Please consider indenting all lines of a {# fun ... #} to match the input indentation, so that this works. -- Ticket URL: <http://hackage.haskell.org/trac/c2hs/ticket/45> c2hs <http://www.cse.unsw.edu.au/~chak/haskell/c2hs/> C->Haskell, An Interface Generator for Haskell

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[c2hs] #43: Please support anonymous enums
by c2hs 05 Jul '12

05 Jul '12

#43: Please support anonymous enums --------------------+------------------------------------------------------- Reporter: guest | Type: defect Status: new | Priority: normal Milestone: | Component: general Version: 0.16.0 | Keywords: --------------------+------------------------------------------------------- c2hs doesn't currently support anonymous enums. Please consider supporting them. Ideally, a single name from the enum should suffice to identify it, and the enum declaration could supply a Haskell name for the enum. -- Ticket URL: <http://hackage.haskell.org/trac/c2hs/ticket/43> c2hs <http://www.cse.unsw.edu.au/~chak/haskell/c2hs/> C->Haskell, An Interface Generator for Haskell

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[c2hs] #44: Foreign pointer declaration produces helper function without type signature, producing warning with -Wall
by c2hs 04 Jul '12

04 Jul '12

#44: Foreign pointer declaration produces helper function without type signature, producing warning with -Wall --------------------+------------------------------------------------------- Reporter: guest | Type: defect Status: new | Priority: normal Milestone: | Component: general Version: 0.16.0 | Keywords: --------------------+------------------------------------------------------- When given a pointer declaration for a foreign pointer, such as: {{{ {# pointer *foo as ^ foreign newtype #} }}} c2hs produces a helper function withFoo, without a type signature. This causes GHC with -Wall to produce a warning message, "Warning: Top-level binding with no type signature". -- Ticket URL: <http://hackage.haskell.org/trac/c2hs/ticket/44> c2hs <http://www.cse.unsw.edu.au/~chak/haskell/c2hs/> C->Haskell, An Interface Generator for Haskell

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