Hi all, I'm trying to make RFC calls to SAP using the nwsaprfc library. Some structs defined in the library contains arrays (byte or word arrays). For example:
typedef struct _RFC_ATTRIBUTES { SAP_UC dest[64+1]; /* RFC destination */ SAP_UC host[100+1]; /* Own host name */ SAP_UC partnerHost[100+1]; /* Partner host name */ SAP_UC sysNumber[2+1]; /* R/3 system number */ SAP_UC sysId[8+1]; /* R/3 system name */ SAP_UC client[3+1]; /* Client */ SAP_UC user[12+1]; /* User */ SAP_UC language[2+1]; /* Language */ ... continued }}RFC_ATTRIBUTES, *P_RFC_ATTRIBUTES; I would like to create a Haskell Storable counterpart of this structure. Using http://therning.org/magnus/archives/tag/hsc2hs as an starting point, I could create Storable for structures containing fields with basic types. Before working on the real data structures I wrote a more simple example to play with: -- File: ArrayStruct.h -- typedef struct _ArrayStruct { char a[10+1]; char b[20+1]; char c[30+1]; } ArrayStruct, *P_ArrayStruct; -- File: ArrayStruct.c -- #include "ArrayStruct.h" void print_array_struct(ArrayStruct *f) { printf("%s\n", __FUNCTION__); printf("f->a: %s\n", f->a); printf("f->b: %s\n", f->b); printf("f->c: %s\n", f->c); } -- File: HArrayStruct.hsc {-# OPTIONS -ffi #-} module Main where import Foreign import Foreign.C.Types #include "ArrayStruct.h" data HArrayStruct = HArrayStruct { a :: String, b :: String, c :: String } type HarrayStructPtr = Ptr HArrayStruct foreign import ccall "static ArrayStruct.h print_array_struct" f_print_array_struct :: ArrayStructPtr -> IO () instance Storable HArrayStruct where sizeOf _ = (#size ArrayStruct) alignment _ = alignment (undefined :: CInt) peek _ = error "peek is not implemented" poke ptr (HArrayStruct a' b' c') = do (#poke ArrayStruct, a) ptr a' (#poke ArrayStruct, b) ptr b' (#poke ArrayStruct, c) ptr c' printArrayStruct as = with as f_print_array_struct main = printArrayStruct $ HArrayStruct { a="some", b="test", c="data" } -- End of files Of course it won't work as HArrayStruct in file HArrayStruct.hs uses Strings and String is not an instance of Storable. Ideally I would need some sort of Storable array of char. Is Data.Storable.Array the type I'm looking for? Could someone point me to some code using the same kind of structures? Thanks, Olivier.
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