#49: Run return value marshaller before output parameter marshallers --------------------+------------------------------------------------------- Reporter: guest | Type: defect Status: new | Priority: normal Milestone: | Component: general Version: 0.16.0 | Keywords: --------------------+------------------------------------------------------- Many C functions provide an error code as a return value, and have output parameters that they do not set unless the return value indicates success. Handling such functions requires checking the return value before running any output marshallers. The reverse situation (an error code as an output parameter that needs checking before the return value) almost never occurs. Thus, run the return value marshaller before the output parameter marshallers, so that the return value marshaller can generate an exception that will prevent the output marshallers from running. {{{ diff -rN -u old-c2hs/src/C2HS/Gen/Bind.hs new-c2hs/src/C2HS/Gen/Bind.hs --- old-c2hs/src/C2HS/Gen/Bind.hs 2012-10-07 19:22:14.515183247 -0700 +++ new-c2hs/src/C2HS/Gen/Bind.hs 2012-10-07 19:22:14.515183247 -0700 @@ -894,8 +894,8 @@ funBody = joinLines marshIns ++ mkMarsh2 ++ call ++ - joinLines marshOuts ++ marshRes ++ + joinLines marshOuts ++ " " ++ (if isImpure || not isPure then "return " else "") ++ ret return $ sig ++ funHead ++ funBody }}} -- Ticket URL: http://hackage.haskell.org/trac/c2hs/ticket/49 c2hs http://www.cse.unsw.edu.au/~chak/haskell/c2hs/ C->Haskell, An Interface Generator for Haskell